January 13 on Coins

My colleague from National Institute of Education, retired professor, Dr Tan Wee Kiat, recently gave our school a hundred copies of his latest book on stamps and coins.

It inspired this problem, a typical upper primary word problem in Singapore school examinations.

Henry has some 10-cent, 20-cent and 50-cent coins.

The ratio of the number of 10-cent coins to the number of 20-cent coins is 7:2 .

The number of 50-cent coins is half the number of 20-cent coins. The total value of the 10-cent coins is $16 more than the total value of 50-cents coins.

How much does Henry have altogether?