The amount she needs more to purchase the bicycle using the coupon is = $25.05
The coupon Christine received from the mall = 5% off sales
The cost of the bicycle the brother wants is = $79
The amount she has saved is = $50
The amount she needs more to purchase the bicycle using the coupon is = X
But, 5% of 79 = 5/100× 79
= 395/100 = $3.95
This means that given the coupon she will purchase the bicycle = 79 - 3.95 = $75.05
Therefore X = $75.05 - $50
= $25.05
Therefore, the amount she needs more to purchase the bicycle using the coupon is = $25.05
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