PSLE
Sarah had two ribbons of the same length. She cut the first ribbon into equal parts of length 80 cm and to each part she tied 3 brown heart cutouts. After that, she cut the second ribbon into equal parts of length 100 cm and to each part she tied 5 red heart cutouts. When she finished tying, she counted that there were 15 more red heart cutouts than brown heart cutouts. How many heart cutouts were there altogether?

	First ribbon	Second ribbon	Difference	Total
Length of each part	80 cm	100 cm
Number of balloons tied to each part	3 brown balloons	5 red balloons
LCM	400 cm	400 cm
Number of equal parts	400 ÷ 80 = 5	400 ÷ 100 = 4
Number of balloons for each ribbon per set	5 x 3 = 15	5 x 4 = 20	20 - 15 = 5	15 + 20 = 35

LCM of 80 and 100 = 400

Number of sets of 3 brown heart cutouts in a length of 400 cm
= 400 ÷ 80
= 5

Number of brown heart cutouts in a length of 400 cm
= 5 x 3
= 15

Number of sets of 5 red heart cutouts in a length of 400 cm
= 400 ÷ 100
= 4

Number of red heart cutouts in a length of 400 cm
= 4 x 5
= 20

Extra number of red heart cutouts in a length of 400 cm
= 20 - 15
= 5

Number of sets of heart cutouts
= 15 ÷ 5
= 3

Total number of heart cutouts in one set of 400 cm of brown balloons and one set of 400 cm of red balloons
= 15 + 20
= 35

Total number of heart cutouts of the two ribbons
= 3 x 35
= 105

Answer(s): 105