A total of n trucks and cars are parked in a slot. If the number of cars is ~$\frac{1}{4}$~ the number of trucks, and ~$\frac{2}{3}$~ of the trucks are pickups, how many pickups, in terms of n, are parked in the slot?
~$\frac{1}{6}n$~
~$\frac{5}{12}n$~
~$\frac{1}{2}n$~
~$\frac{8}{15}n$~
~$\frac{11}{12}n$~
sorry,是8/15n
cars为a,trucks为b。
n=a+b. a=1/4b.
推出n=5/4b, b=4/5n
p是b的2/3 所以p=8/12n
这道题谁会,帮忙讲一下呗