作业帮求一道SAT数学题One-fifth of the cars in a parking lot are blue and half of the blue cars are convertibles.If 1/4 of the convertibles in the parking lot are blue,than what percent of the cars in the lot are neither blue nor convertibles.我么
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求一道SAT数学题One-fifth of the cars in a parking lot are blue and half of the blue cars are convertibles.If 1/4 of the convertibles in the parking lot are blue,than what percent of the cars in the lot are neither blue nor convertibles.我么
求一道SAT数学题
One-fifth of the cars in a parking lot are blue and half of the blue cars are convertibles.If 1/4 of the convertibles in the parking lot are blue,than what percent of the cars in the lot are neither blue nor convertibles.
我么知道为啥每次做都和正确答案差了10%....
求一道SAT数学题One-fifth of the cars in a parking lot are blue and half of the blue cars are convertibles.If 1/4 of the convertibles in the parking lot are blue,than what percent of the cars in the lot are neither blue nor convertibles.我么
占5分1的蓝车有一半是开篷,即开篷蓝车占10分1,4分1的开篷车是蓝车,所以开篷车占总数2/5,所以既不蓝也不开篷就1-1/5-2/5+1/10=50% 因为蓝色开开篷对于开篷和蓝车重复了,所以要加回一次
# of Neither blue nor convertibles = total car number - (blue car number + convertibles number - blue and convertibles car number)
Total cars number = 1
blue cars number = 1/5
blue and con...
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# of Neither blue nor convertibles = total car number - (blue car number + convertibles number - blue and convertibles car number)
Total cars number = 1
blue cars number = 1/5
blue and convertibles cars number = (1/5) * (1/2) = 1/10 since "half of the blue cars are convertibles"
convertibles number = 4 times of "blue and convertibles cars number" = (1/10) * 4 = 4/10 = 2/5, since "1/4 of the convertibles in the parking lot are blue"
therefore the final result would be 1 - ( 1/5 + 2/5 - 1/10) = 1 - 5/10 = 5/10 = 0.5 = 50%
Hope that would help
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