if a : b : : 3 : 4 , then what is ( 5 a + 6 b ) : ( a - 2 b ) ?
"a / b = 3 / 4 dividing numerator & denominator of ' ( 5 a + 6 b ) / ( a - 2 b ) ' by b , [ 5 ( a / b ) + 6 ] / [ ( a / b ) - 2 ] = [ 5 * ( 3 / 4 ) + 6 ] / [ ( 3 / 4 ) - 2 ] = - 39 / 5 answer : d"
divide(add(multiply(5, 3), multiply(4, 6)), subtract(3, multiply(2, 4)))