Question

If 840 is divided between a and b in the 5 : 2 after 5 years their ages will be in the ratio 15 : 7 the present age of a is

Answer 1

$let \: the \: ag \: in \: ratio \: be \: 5xand2x \: then \: \\ 5x + 5 \div 2x + 5 = 15 \div 7 = \\ 7(5x + 5) = 15(2x + 5) \\ 35x + 35 = 30x + 75 \\ 35x - 30x = 75 - 35 \\ 5x = 40 \\ x = 40 \div 5 \\ x = 8$