jacob is 18 years old . he is 2 times as old as his brother . how old will jacob be when he is twice as old ?
j = 18 ; j = 2 b ; b = 18 / 2 = 9 ; twice as old so b = 9 ( now ) + ( 9 ) = 18 ; jacob is 18 + 18 = 36 answer : a
multiply(18, 2)