A man borrows 40,000 on a short term loan and is charged interest of 1naira on each 10naira per week. How much does he pay back altogether, if he borrows the money for 1 week?

The man borrowed 40,000 naira, and the interest rate is 1 naira on each 10 naira borrowed.

Therefore, the total interest for borrowing 40,000 naira would be:

40,000 / 10 = 4,000 naira

So the total amount the man would have to pay back altogether is:

40,000 + 4,000 = 44,000 naira

Therefore, he would have to pay back 44,000 naira altogether if he borrowed the money for 1 week.