Doughnuts

[SILVER]

Im stuck on this problem. The answer is eight pounds, but how do you get there?

Four chocolate Waddle doughnuts and a jelly doughnut weigh 20 pounds. Nine chocolate Waddle doughnuts and two jelly doughnuts weigh 43 pounds. How much does a jelly doughnut weigh?

 

[soroban]

Hello, SILVER!

I'm stuck on this problem. The answer is eight pounds, but how do you get there?

Four chocolate Waddle doughnuts and a jelly doughnut weigh 20 pounds.
Nine chocolate Waddle doughnuts and two jelly doughnuts weigh 43 pounds.
How much does a jelly doughnut weigh?

Let C = weight of a chocolate donut.
Let J = weight of a jelly donut.

The two statements give us these two equations:

. . 4C + .J .= .20
. . 9C + 2J .= .43

Now so=olve the system . . .