Tao Nan School P5 SA2 2006 Math Q39

An orange cost ½ as much as a watermelon. Jiamin paid $21 for 12 watermelons and 6 oranges. How much did she pay for the 6 oranges?

Solution

Orange ----- 1 unit
Water Melon ----- 2 units

12 water melons + 6 oranges ----- $21
(12 x 2 units) + 6 units ----- $21
24 units + 6 units ----- $21
30 units ----- $21
1 unit ------ $21 divided by 30 = $0.70

(6 oranges) 6 units ----- 6 x $0.70 = $4.20

Answer: She paid $4.20