First solve what is probably 'part A.'
Peter has 36 ÷ 4; Peter has 9 model cars. Jade has 3 times as many as Peter; Peter has 1/3 as many as Jade, so 9 x 3 = 27, so Jade has 27 cars.
1st equation: 36 ÷ 4 = 9 -OR- 36 x 1/4 = 9
2nd equation: 9 x 3 = 27 -OR- (36 x 1/4) x 3 = 9
(36/4)3 = 9 would also work. I think the 1st equations would be best... just giving some choices...
hope this helped!