Question

Eva has £6.05 in her moneybox.

She only has 20p,10p and 5p coins.

For every two 10p coins in the box,Eva has one 20p coin and three 5p coins.


How many of each coin does Eva have in her moneybox?

Answer 1

11 of 20p, 22 of 10p and 33 of 5p

Explanation:

Eva has 20p, 10p and 5p coins, total of £6.05 = 605p

Let 20p=x, 10p=y, 5p=z

Then:

• 20x + 10y + 5z = 605
• y : x = 2 : 1 ⇒ x= y/2
• y : z = 2 : 3 ⇒ z= 3y/2

Rewriting the first equation considering next two:

• 10y + 10y + 7.5y = 605
• 27.5y = 605
• y= 605/27.5
• y= 22
• x= y/2 = 22/2 = 11
• z = 3y/2 = 3*11 = 33

Answer: 11 of 20p coins, 22 of 10p coins and 33 of 5p coins