# Elle went to Pet Smart and bought 4 goldfish and 3 turtles for $28. Later that day, Warren went to Pet Smart and bought 6 goldfish and 1 turtle for$10. How much does 1 goldfish cost?

Oct 7, 2015

Price of gold fish $$\frac{1}{7}$#### Explanation: Let $g$be the price of goldfish Let $t$bt the price of turtles Then - $4 g + 3 t = 28$----------------(1) $6 g + 1 t = 10$------------------(2) Solve the 1st equation for $t$$t = 10 - 6 g$$4 g + 3 \left(10 - 6 g\right) = 28$$4 g + 30 - 18 g = 28$$- 14 g = 28 - 30 = - 2$$g = \frac{- 2}{- 14} = \frac{1}{7}$Price of gold fish$$\frac{1}{7}$

This is optional. This is not asked in the prolem
Substitute the value $g = \frac{1}{7}$ in equation (2)

$4 \left(\frac{1}{7}\right) + 3 t = 28$
$4 + 21 t = 196$
$21 t = 196 - 4 = 192$
$t = \frac{192}{21}$

Price of one turtle $$\frac{192}{21}\$