Youssef can either way from his home to his workplace or ride his bicycle. he walks at a pace of 1 block per min, but he can travel 1 block in 20 sec on his bicycle. if it takes youssef 10 min longer to walk to work than to ride his bike, how many blocks away from work does he live ?

Youssef lives 15 blocks away from his work

Solution:

Given that Youssef can either way from his home to his workplace or ride his bicycle

Let "x" be number of blocks away from work Youssef works

Case 1: walking

He walks at a pace of 1 block per min

Therefore,

1 block = 1 minute

Thus to cross "x" blocks he takes "x" minutes

Case 2: Bicycle

He can travel 1 block in 20 sec on his bicycle

We know that,

To convert seconds to minute, divide the time value by 60

Thus he takes 1/3 minutes for 1 block

So to cross "x" blocks he will take minutes

Given that it takes youssef 10 min longer to walk to work than to ride his bike

This means difference between time taken to cross "x" blocks by walking and ride by bicycle is 10 minutes

Thus he lives 15 blocks away from his work

since proposition states that a number is greater than 25, if is true then the number must actually be greater than 25.

this implies that all possible options, except 24, can be accepted