Answer:
$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 = ![\frac{2,100}{50} = 42\ coins](https://tex.z-dn.net/?f=%5Cfrac%7B2%2C100%7D%7B50%7D%20%3D%2042%5C%20coins)
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