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MathRevolution
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If t1 hours are required to travel d miles at v1 miles per hour and t2 08 May 2016, 05:27
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66% (01:58) correct 34% (01:58) wrong based on 509 sessions

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If t1 hours are required to travel d miles at v1 miles per hour and t2 hours are required to travel the same d miles at v2 miles per hour, is the overall average speed equal to (v1+v2)/2?

(1) t1 = t2
(2) v1 = v2


(A) Statement 1 alone is sufficient, but statement 2 alone is not.
(B) Statement 2 alone is sufficient, but statement 1 alone is not.
(C) Both statements together are sufficient, but neither alone is sufficient.
(D) Each statement alone is sufficient.
(E) Neither statement is sufficient, even when combined.
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D
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Himanshu9818
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If t1 hours are required to travel d miles at v1 miles per hour and t2 08 May 2016, 12:45
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MathRevolution
If t1 hours are required to travel d miles at v1 miles per hour and t2 hours are required to travel the same d miles at v2 miles per hour, is the overall average speed equal to (v1+v2)/2?
1) t1=t2
2) v1=v2

* A solution will be posted in two days.
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Ans D
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TIMEBBA
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If t1 hours are required to travel d miles at v1 miles per hour and t2 08 May 2016, 09:50
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The Answer is C.I solved i the old traditional way.
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If t1 hours are required to travel d miles at v1 miles per hour and t2 08 May 2016, 21:42
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Avg speed= (D1 + d2 + d3 +....... Dn)/(t1+ t2+t3 +..... tn) = ( V1*t1 + V2*t2 + V3*t3 +.......... Sn*tn)/(t1+ t2+t3 +..... tn)

so now for given ques , avg speed= (V1*T1 + V2*T2)/T1+T2.............................. (1)

1st statement , t1=t2 ==> (1) gets reduced to avg speed = (V1+ V2)/2 Sufficient

2nd statement, v1=v2 ==> (1) GETS REDUCED TO avg speed = V1=V2 which is equal to (V1+V2)/2 since both are equal.

Hence Ans D
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If t1 hours are required to travel d miles at v1 miles per hour and t2 09 May 2016, 20:43
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There are 5 variables (v1, t1, v2, t2, d) and two equations (v1t1=d, v2d2=d) in the original condition. In order to match the number of variables to the number of equations, we need 3 equations. Therefore, there is high chance that E is the correct answer. Using both the condition 1) and the condition 2), we get the condition 1)=the condition 2). The answer is always yes and the conditions are sufficient. Hence, the correct answer is D.

- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
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If t1 hours are required to travel d miles at v1 miles per hour and t2 26 Dec 2016, 08:59
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MathRevolution
If t1 hours are required to travel d miles at v1 miles per hour and t2 hours are required to travel the same d miles at v2 miles per hour, is the overall average speed equal to (v1+v2)/2?
1) t1=t2
2) v1=v2

* A solution will be posted in two days.
Show more

Since it is mentioned that D1=D2, taking any of the T1=T2 or V1=V2 will equate the other dimension. Please correct me if I am wrong.
I think it should be Option D
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If t1 hours are required to travel d miles at v1 miles per hour and t2 24 Jun 2025, 12:44
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Hi, Please Help....

t1, v1 and t2,v2 ..and d is same for both..Can't we just solve this..Like....(v1 + v2)/2....
So average speed will be possibel( v1 +v2.)/2 ..this would be possible when v1 and v2 are equal...Since D is equal

1. Says t1, t2 are equal..and d is equal so v1, v2 are equal
2. Says v1, v2 are equal.....
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If t1 hours are required to travel d miles at v1 miles per hour and t2 04 Oct 2025, 04:48
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Bunuel

we could have solved it just by saying
if time is equal for equal distance then speed has to be equal
hence 1 suff.
is this ok?
MathRevolution
If t1 hours are required to travel d miles at v1 miles per hour and t2 hours are required to travel the same d miles at v2 miles per hour, is the overall average speed equal to (v1+v2)/2?

(1) t1 = t2
(2) v1 = v2
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