Yutong's answer to IDK's Primary 5 Maths Fractions Singapore question.
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Convert the question into 2 equations:
1. (2/9)Red = (3/4)Blue
2. Red + Blue = 490
Using equation 1, express Red in terms of Blue:
(2/9)Red ÷ (2/9) = (3/4)Blue ÷ (2/9)
Red = (3/4)÷(2/9) Blue
Red = (27/8) Blue
Then, substitute this equation into equation 2:
(27/8)Blue + Blue = 490
((27/8) + 1)Blue = 490
(35/8)Blue = 490
Blue = 14×8 = 112
Blue is the initial number of blue, hence to find the number of blue left:
(1/4)Blue = 112÷4 = 28
1. (2/9)Red = (3/4)Blue
2. Red + Blue = 490
Using equation 1, express Red in terms of Blue:
(2/9)Red ÷ (2/9) = (3/4)Blue ÷ (2/9)
Red = (3/4)÷(2/9) Blue
Red = (27/8) Blue
Then, substitute this equation into equation 2:
(27/8)Blue + Blue = 490
((27/8) + 1)Blue = 490
(35/8)Blue = 490
Blue = 14×8 = 112
Blue is the initial number of blue, hence to find the number of blue left:
(1/4)Blue = 112÷4 = 28
Date Posted:
3 years ago
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