maths (f. 1)

1. 96 passengers got off a train from HK and Shenzhen. 75% of the remaining passengers got off at Guangzhou. Finally 76 passengers were still on the train.
> Find the number of passengers on the train when the train left Shenzhen.

2. A man sells two machines at $19800 each. He makes a profit of 10% on the machine and suffers a loss of 10% on other. On the whole, find
> his profit or loss
> his profit % or loss%

3. A watch was marked at $1200 by a manufacturer. The watch was sold at 15% discount to a shopkeeper. The shopkeeper marked the price of the watch as $x and offered a 10% discount. After the shopkeeper sold the watch, he made a 20% profit. Find the value of x

4. Tommy worked in a bank. He borrowed $250 000 from the bank at R% p.a. simple interest and agreed to repay all the money one year later. After six months, Tommy owed the bank $255000 and he resigned at that time. The bank then added 6% p.a. to the interest rate. Find the amount that Tommy owed the bank when the loan was due.

5. Andy deposits $50000 in a bank at a certain simple interest rate. If he gets anamount of $56975 after 2.5 years, what is the interest rate per annum?

5. A sum of money is deposited in Bank A for 1.5 years at an interest rate of 5%p.a.. Same amount of money is deposited in Bank B for 0.5 year at an interest rate of 15% p.a.. Are the simple interests received from these two deposits the same?
> Let $P be the sum of money.
} Interest received from Bank A
} Interest received from Bank B

7. Kelly borrowed $4800 from a bank at an interest rate of 10% p.a. for 8 month. Wendy borrowed $20000 from the same bank at an interest rate of 24% p.a.. If Wendy paid $80 more as interest than Kelly, how long did Wendy borrow the money?
Interest paid by Kelly
= $4800x10%x8/12
= $320
Suppose Wendy borrowed the money for n months.
Interest paid by Wendy
= $20000x24%x8/12
= $3200
∵ Wendy paid $80 more as interest than Kelly.
∴ _________ = ________ + 80
n = _________

step pls