5. John has 150 coins. When he throws them on the table, $40 \%$ of them show heads and $60 \%$ of them show tails. How many coins showing tails does he need to turn over to have the same number showing heads as showing tails?
A 10
B 15
C 20
D 25
E 30
Solution
B

The number of coins that currently show heads is $40 \%$ of 150 , which is 60 . To have the same number of heads showing as tails, John needs 75 coins showing heads. Therefore the number of coins he needs to turn over is $75-60=15$.