Question

The ratio of the number of student studying in schools A, B and C is $6:8:7$ respectively if the number of student studying in each of the schools is increased by $20\%,15\%$ and $20\%$ respectively then what will be the new ratio of the number of student in school A, B and C ?

• A. $18:23:21$
• B. $16:28:30$
• C. $20:12:36$
• D. $22:21:12$

Answer 1

The correct option is A $18:23:21$

The ratio of the number of students studying in school A, B, C.

$=6:8:7$

Suppose number of student's in school

$A=6x$

$B=8x$

$C=7x$

It will be Increased by

$A=6x+6x\times 20$ %

$=6x+\frac{6x\times 20}{100}$

$=6x+\frac{6x}{5}$

$=\frac{30x+6x}{5}$

$=\frac{36x}{5}$

$B=8x+\frac{8x\times 15}{100}$

$=8x+\frac{6x}{5}$

$=\frac{46x}{5}$

$C=7x+\frac{7x\times 20}{100}$

$=\frac{35x+7x}{5}$

$=\frac{42x}{5}$

New Ratio $=\frac{36x}{5}:\frac{46x}{5}:\frac{42x}{5}$

$=36:46:42$

$=18:23:21$