Question

the strength of school increased by 10% during 1year and then by 20%during next year the total number of students then became 528 find the original strength of the school

Answer 1

$sppose \: original \: is \: x \\ x \times \frac{110}{100} \times \frac{120}{100} = 528 \\ \frac{528 \times 100 \times 100}{110 \times 120} = 400 = \: ans$