PSLE
Hilda had two ribbons of the same length. She cut the first ribbon into equal parts of length 25 cm and to each part she tied 2 grey heart cutouts. After that, she cut the second ribbon into equal parts of length 30 cm and to each part she tied 3 black heart cutouts. When she finished tying, she counted that there were 15 more black heart cutouts than grey heart cutouts. How many heart cutouts were there altogether?

	First ribbon	Second ribbon	Difference	Total
Length of each part	25 cm	30 cm
Number of balloons tied to each part	2 grey balloons	3 black balloons
LCM	150 cm	150 cm
Number of equal parts	150 ÷ 25 = 6	150 ÷ 30 = 5
Number of balloons for each ribbon per set	6 x 2 = 12	3 x 5 = 15	15 - 12 = 3	12 + 15 = 27

LCM of 25 and 30 = 150

Number of sets of 2 grey heart cutouts in a length of 150 cm
= 150 ÷ 25
= 6

Number of grey heart cutouts in a length of 150 cm
= 6 x 2
= 12

Number of sets of 3 black heart cutouts in a length of 150 cm
= 150 ÷ 30
= 5

Number of black heart cutouts in a length of 150 cm
= 5 x 3
= 15

Extra number of black heart cutouts in a length of 150 cm
= 15 - 12
= 3

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

Total number of heart cutouts in one set of 150 cm of grey balloons and one set of 150 cm of black balloons
= 12 + 15
= 27

Total number of heart cutouts of the two ribbons
= 5 x 27
= 135

Answer(s): 135