Question

Solve $91:?::64:54$

• A. 63
• B. 101
• C. 32
• D. 70

Answer 1

The correct option is D 70

The answer is $70.$

We can write

$64=8\times 8$

$54=9\times 6$

$64:54=(8\times 8):(9\times 6)$

Observe the above pattern, we have

$9=8+1$

1st factor of 2nd number = 1st factor of 1st number +1

$6=8-2$

2nd factor of 2nd number = 2nd factor of 2nd number -2

Therefore for $91:\underset{–}{m\times n}$

$91=13\times 7$

$m=13+1=14$

and, $n=7-2=5$

$\therefore m\times n=14\times 5=70$

Hence, $91:70::64:54$

Alternate way:

if you look at $64:54$ it is $(8\cdot 8):(9\cdot 6)$

basically, $n\cdot m:(n+1)\cdot (m-2)$

So, $13\cdot 7$ becomes $14\cdot 5=70$