The price of A is double that of B. If the price of A is increased by10% and that of B is increased by 25%, then what is the percentage increase in the total price of A and B together?
20%
16%
12%
15%
Solution
Let the price of B be Rs. 100
The price of A will be Rs. 200
Total price of A and B = 1000 + 200 = Rs. 300
The price of A after 10% increase
$=200\times \left( 1.1 \right)=Rs.220$
The price of B after 25% increase
$=100\times \left( 1.25 \right)=Rs.125$
$\therefore $ Total price 220 + 125 = Rs. 345
The percentage increase $=\left( \frac{345-300}{300} \right)\times 100$
$ = \frac {45}{300}\times 100=15\%$