3/7 * 15/12

Question

how would I solve the fraction 3/7 * 15/12 when I mulitplied straight across then I got 45/84

Answer 1

(3/7) x (15/12) = (3 x 15) / (7 x 12) = 45 / 84

 

Your answer is correct, but you can simplify it a little by factoring it into prime numbers.

 

45 = 3 x 3 x 5

84 = 2 x 2 x 3 x 7

 

45 / 84 = (3 x 3 x 5) / (2 x 2 x 3 x 7)

 

Note both the numerator and denominator have a 3.

 

45 / 84 = (3 x 5) / (2 x 2 x 7) = 15 / 28

Answer 2

3/7 * 15/12

(3 * 15) / (7 * 12)

(1 * 15) / (7* 4)    reduce

15 / 28

 

45/84 reduces to 15/28