Roslan had a total of $50 in 10-cent coins,20-cent coins and 50-cent coins. The value of his 10-cent coins was 30% of the total value of all his coins. The value of his 20-cent coins was 28% of the total value of all his coins. What was the value of his 50-cent coins?

$21

Step-by-step explanation:

Provided total value = $50

$50 = 5,000 cents.

We are provided,

10 cent coins value = 30%  of total value

= 0.3 5,000 cents = 1,500 cents

Value of 20 cents coin = 28% of total value

= 0.28 5,000 cents = 1,400 cents

Therefore, remaining value of cents = Total value of 50 cents coins

5,000 cents - value of 10-cent coins - value of 20-cent coins = total value of 50 cents coins

5,000 - 1,500 - 1,400 = 2,100 cents = $21

Which means number of 50 cents coin =

Alternatively,

To calculate value of 50 cent coins

Total value = 100%

Value in 10-cent coins + 20-cent coins = 30% + 28% = 58%

Value in 50-cent coins = 100 - 58 = 42%

= $50 42% = $21