At first, Mary had some 20-cent coins and 10-cent coins in the ratio 4:1. After exchanging two 20-cent coins for 10-cent coins, the difference between the values of 20-cent coins and 10-cent coins was $1.50. How much money did Mary have at first?

Hi, please help me with these 2 questions, is urgent, many thanks!


Nancy has 10-cent and 20-cent coins in the ratio of 5:6. When she spends eight 20-cent coins, the value of 20-cent coins is $0.20 less than that of the 10-cent coins. How many 10-cent coins does Nancy have?

Hi tianzhu, thanks alot for the solution!

Please help with this ratio question and many thanks in advance…


At a carnival, there were 40% more males than females. There was an equal number of males without caps to the number of females without caps. The number of males with caps to the number of female with caps was 6:2.

a. What was the ratio of the number of females with caps to the number of females without caps?

b. Midway, 800 females left the carnival. In the end, there were 3/7 as many females as males remaining behind. How many people were at the carnival at first?

Hi tianzhu, now I understand and it seems simple too! Thank you very much for your time!!

Please help with this speed question and many thanks in advance…


Amy and Betty ran in a race. When Amy has completed 7/8 of the distance, Betty had only completed 2/3 of the distance of the race.

Amy’s average speed for the race was 80m/min faster than Betty’s. What was Betty’s average speed for the race in m/min?