



 
Hi Tasmin, There are two important quantities here, the number of coins and the value of the coins. Suppose that Graham has $t$ 10 shilling coins and $f$ 5 shilling coins. The total number of coins he has is $t + f$ and you know this number is 24. Hence \[t + f = 24.\] This is the first important quantity, the other is the value of the coins. What is the total value of his 10 shilling coins? What is the total value of his 5 shilling coins? What is the total value of his coins? You know this value is 150 shillings. This gives you a second equation in $t$ and $f.$ Solve for $t$ and $f.$ Penny  


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