# Ten years ago, A was half of B in age. If the ratio of their present ages is 3 : 4, what will be the total of their present ages ?

$\par&space;Let&space;the&space;ages&space;of&space;A&space;and&space;B&space;10&space;years&space;ago&space;be&space;x&space;and&space;2x&space;years&space;respectively.$

$\frac{x+10}{2x+10}&space;=&space;\frac{3}{4}$

$4(x&space;+&space;10)&space;=&space;3(2x&space;+&space;10)$

$2x&space;=&space;10$

$x&space;=&space;5$

$\par&space;Sum&space;of&space;their&space;present&space;ages&space;=&space;(x&space;+&space;10)&space;+&space;(2x&space;+&space;10)&space;=&space;(3x&space;+&space;20)&space;=&space;35&space;years$