There are 18 girls in the class and 6 boys.
D. 39.5 is the likely hood of the students likeing burgers and hotdogs based on the information given
X + 4x = 75
Combine like terms:
5x = 75
Divide by 5 on each side of the equal sign:
x = 15
The Answer is b: x = 18, y = -20
Proof:
Solve the following system:
{4 x + 3 y = 12 | (equation 1)
{7 x + 5 y = 26 | (equation 2)
Swap equation 1 with equation 2:
{7 x + 5 y = 26 | (equation 1)
{4 x + 3 y = 12 | (equation 2)
Subtract 4/7 × (equation 1) from equation 2:
{7 x + 5 y = 26 | (equation 1)
{0 x+y/7 = (-20)/7 | (equation 2)
Multiply equation 2 by 7:
{7 x + 5 y = 26 | (equation 1)
{0 x+y = -20 | (equation 2)
Subtract 5 × (equation 2) from equation 1:
{7 x+0 y = 126 | (equation 1)
{0 x+y = -20 | (equation 2)
Divide equation 1 by 7:
{x+0 y = 18 | (equation 1)
{0 x+y = -20 | (equation 2)
Collect results:
Answer: {x = 18, y = -20
