Let's use S for the number of shaddocks and W for the number of watermelons.
S + W =15
1.8S + 2.5W = 33.30
Let's solve S+W=15 for S.
S = 15 - W
Now we can use substitution to solve the system of equations. To do so, plug in 15-W for S in the second equation.
1.8(15-W) + 2.5W = 33.30
Distribute and combine like terms.
27 - 1.8W + 2.5W = 33.30
0.7W + 27 = 33.3
0.7W = 6.3
W = 9
If there are 9 watermelons, then there are 15 - 9 = 6 shaddocks.
The answer is 6 shaddocks and 9 watermelons.
