PSLE
Zara had two streamers of the same length. She cut the first streamer into equal parts of length 50 cm and to each part she tied 2 black heart cutouts. After that, she cut the second streamer into equal parts of length 90 cm and to each part she tied 4 green heart cutouts. When she finished tying, she counted that there were 10 more green heart cutouts than black heart cutouts. How many heart cutouts were there altogether?

	First streamer	Second streamer	Difference	Total
Length of each part	50 cm	90 cm
Number of balloons tied to each part	2 black balloons	4 green balloons
LCM	450 cm	450 cm
Number of equal parts	450 ÷ 50 = 9	450 ÷ 90 = 5
Number of balloons for each streamer per set	9 x 2 = 18	4 x 5 = 20	20 - 18 = 2	18 + 20 = 38

LCM of 50 and 90 = 450

Number of sets of 2 black heart cutouts in a length of 450 cm
= 450 ÷ 50
= 9

Number of black heart cutouts in a length of 450 cm
= 9 x 2
= 18

Number of sets of 4 green heart cutouts in a length of 450 cm
= 450 ÷ 90
= 5

Number of green heart cutouts in a length of 450 cm
= 5 x 4
= 20

Extra number of green heart cutouts in a length of 450 cm
= 20 - 18
= 2

Number of sets of heart cutouts
= 10 ÷ 2
= 5

Total number of heart cutouts in one set of 450 cm of black balloons and one set of 450 cm of green balloons
= 18 + 20
= 38

Total number of heart cutouts of the two streamers
= 5 x 38
= 190

Answer(s): 190