Car a and car B transported a batch of coal. Car a transported 30% of the coal first, and the rest was distributed to car a and car B according to 2:5. At the end of the ceremony, car B transported 30 tons of coal I know the answer is 60, what is the process, and why

Car a and car B transported a batch of coal. Car a transported 30% of the coal first, and the rest was distributed to car a and car B according to 2:5. At the end of the ceremony, car B transported 30 tons of coal I know the answer is 60, what is the process, and why

100% - 30% = 70%, 70% △ 2 + 5 for a share, (result × 5 = 30 tons) = 50% of this batch of coal = 30 tons × 2 = 60 tons. Do you understand?

A project is divided equally between Party A and Party B working at the same time for eight days. Only two-thirds of the project is completed. It is known that the work efficiency of Party A is 150% of that of Party B. how many days will Party B have to work to complete the task assigned to him?

If the whole project is 1, B completes x every day, then a completes 1.5x every day
8（x+1.5x）=2/3
x=1/30
Because Party A and Party B share the whole project equally, the time required for Party B to complete his task is 0.5 △ 1 / 30 = 15 days
So Party B still needs 15-8 = 7 days to complete the task
If it is helpful, please comment and adopt it as a satisfactory answer, thank you