Bài 1: Joel is 8 years old. His mother is 34 years old. In how many years' time will his mother's age be three times Joel's age ?
Bài 2: The average of A and B is 20. The average of B and C is 15. The average of C and D is 18. Find the average of A and D ?
( Giải giúp mk với)
bài 2:đáp án là 50
câu 1 thì mk k bt làm
bạn làm bài giải giúp mk với