1.There were 192 oranges and melons in a box. Mr Liu removed 2/5 of the oranges from the box and he added 24 melons into the box. As a result, there was an equal number of oranges and melons left in the box.
How many more oranges than melons were there in the box at first ?
2. There are some yellow and green balls in a basket.
The sum of 3/8 of the number of yellow balls and all the green balls is 430. The sum of 1/2 of the number of yellow balls and 1/4 of the number of green balls is 192. How many green balls are there in the basket ?
3. Starting from the same position on a straight road, Timothy and Michael jogged in the opposite direction. With Timothy jogging at an average speed of 1.6 km/h slower than Michael, the two men were 4.2 km apart after jogging for 45 minutes. Find the average speed of Michael. (Give your answer in km/h).
4. Mrs Tan had 98 pieces of $10 notes and $50 notes in her piggy bank.
She took out 3/4 of the $50 notes and put in another ten $10 notes.
As a result, the number of $10 notes was five times the number of $50 notes.
What was the total value of money she had in her piggy bank at first?