today jj

wanglijie

Among a batch of cars, a 74% of them have A, and a 71% of them have B. What is the percent of the cars that have both?
  1)the percent of the cars that have B but not A is 11%
  2)the percent of the cars that have both is twice the percent that have neither A nor B
Ans
请教思路

windyyang

【思路】1) 71% -11%=60%
2) x=2[100-(74+71-x)], 得x=90. the percent of the cars that have both is 90%