Answer: He bought 4 cupcakes and 12 donuts
Explanation:
He bought three times as many donuts as cupcakes so we could represent that by the equation d= 3c where d is donuts and c is the cupcakes.
If cupcakes also cost 50 cent and donuts cost a dollar each and he spent a total of 10 dollars then we could also represent that by the equation
0.50d + 1c = 10
Now combine use the two equations and solve for d and c
d= 3c
0.50d + 1c =10 substitute d in the first equation into the second equation.
0.50(3c) + 1c =10
1.5c + 1c =10
2.5c = 10
c= 4
In this case he bought a total of 4 cupcakes and to find the total of donuts that he bought we multiply that by 3 because he bought three times as much as that.
d= 3 * 4
d = 12