shivimonji
TestPrepUnlimited
axezcole
Mike visits his childhood friend Alan at a regular interval of 4 months. For example, if Mike visits Alan on 1st Jan, his next visit would be on 1st May and so on. He started this routine on his 25th birthday. Yesterday, he celebrated his Nth birthday. How many visits has Mike made so far (including the first visit on his 25th birthday)?
a)n – 24
b)2n – 50
c)2n – 49
d)3n – 75
e)3n – 74
We can try to find the answer by using some test points. When n = 26, Mike would have visited 1 + 3 = 4 times. When n = 27, Mike would have visited 1 + 3 + 3 = 7 times. We can see each increment in \(n\) would increase the number of visits by 3, so the function here should have \(3n\).
Looking at the answers we need to decide between D and E, we can then plugging in to check which one is correct. With D, when n = 26 we have \(3n - 75 = 78 - 75 = 3\) visits when the answer should be 4. Then E has to be the correct answer.
Ans: E
I am still confused when it says included in the question stem then why are we subtracting 1..????
please help....
Hey there ,
Let me try to make you understand the approach that I followed .
1) Consider you are now 25 yrs old and your friend visits your 3 times /year ( as per the question ) .
2) On your 27th Birthday , how many times in total he will visit you ? ?
3) Just use simple calculation :
(27th birthday - 25th birthday ) = 2
Now , your frn is going to visit you : 2* 3 times + 1 times ( that’s on your 27th birthday )
So , total 7 times
Now let’s look into the question :
(Nth birthday - 25 )3 + 1
-> (N - 25)3 + 1 => 3N -75+1 => 3N -74
Hope this helps
Posted from my mobile device