Victoria E.

asked • 11/06/18

160 yellow and blue balls in a box. 2/5 of yellow balls are removed, 2/3 of blue balls are removed. Total number of balls now left in the box is 72. How many blue balls were there at the start?

Please can someone help?

1 Expert Answer

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Paul M. answered • 11/07/18

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Y + B = 160


160 - (2/5)Y - (2/3)B = 72

(2/5)Y + (2/3)B = 88

Multiply by 15

6Y + 10B = 1320

3Y + 5B = 660


3Y + 3B = 480 (from the first equation)


2B = 180

B = 90

Y = 70

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Victoria E.

Fabulous! For some reason couldn't put algebra together...now I see! Many thanks.
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11/07/18

Victoria E.

except that is a plus sign, not a minus in first equation
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11/07/18

Emily S.

why are you multiplying by 15?
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11/07/18

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