Let the cost of 2-scoop cones be x, and the cost of sundaes be y.
The first statement tells us that 5x = 3y
The second statement tells us that 9x + 6y = 19.95
Then we need to calculate the value of y (the cost of a sundae).
From our first equation, y = 5x/3. Substituting this into the second equation:
9x + 6(5x/3) = 19.95
9x + 10x = 19.95
19x = 19.95
x = 1.05
Substituting back into the first equation: 5(1.05) = 3y
5.25 = 3y
y = 1.75
Therefore the cost of a sundae is $1.75.
