Test: Playing With Numbers - CAT MCQ

Correct Answer :- b

Explanation : 1+9+7 +4 + 2(power) so the answer will 23 and if we add 5+6+4+2(power) so the answer will 17.

We have 7+5=12, 1 is carried forward, so 1+N+8=_5, which gives N=6

Adding one’s place 5+7+8=20, 2 is carried forward.adding the ten’s place 2+3+9+8=22, this means A=2

We have A*4=_8 so A can be 2 or 7.now if A is 7,then we have 2 as carried forward so 4*3+2=14_7A,when A=2, we have no carried forward so4*3=12=_2=A. Hence A=2

As we see the addition part,we have 23PPQ, this means that we don’t have any carried forward for the thousand’s place this means we have only single digit by adding Q and P, so Q+P =P only when Q=0,and now seeing the multiplication we have 3*P=_P which is only possible when P=5.

The numbers ending with 2,4,6,8 ,0 are divisible by 2.

Looking at the addition of the hundred’s place we have 7+7+2=_A which gives A=6. Coming back to the multiplication which is A*B=B where A=6 ,so B can be 4 or 6, but when you take B=6, we have 3 as carried forward and 7*6+3 is not equal to 0. Hence B=4 and A=6.

Since N leaves the remainder of 4 when divided by 5. the possible values in ones place of number N are 4 or 9.

now, since it leaves a remainder of 1 when divided by 2, the N would be an odd number. hence ones digit of N is also an odd number. which means ones digit of our number N is 9.