pushpitkc wrote:

In the time taken by Morton to take 4 steps, Lindsey takes 5 steps. If Morton's three steps are equal to

Lindsey's four steps and Lindsey's speed is 7.5 miles/hour, what is Morton's(approximate) speed?

A. 6

B. 7

c. 8

D. 9

E. 10

Source:

Experts GlobalLet's get Morton's steps to same base... LCM of 3 and 4 is 12

Morton's 3 steps = L's 4...

So M's 3*4 or 12 =L's 4*4=16 steps...

But when M takes 4, L takes 5,

So when M takes 4*3, L takes 5*3

That is when K covers 15 steps, M covers 16 equivalent steps

Speed M: L =16:15...

If 7.5 is 15, 16 will be 16*7.5/15=8

_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

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