Question 1152152
Let the cost of a shark eraser be s and the cost of a keychain k. We have the system of equations, {{{system(5s+k=2.20,2s+6k=3.40)}}} Dividing the second equation by two and multiplying by five gets {{{system(5s+k=2.20,5s+15k=8.50)}}} Subtracting the first equation from the second gets {{{14k=6.30}}} Dividing by 14 gets k=0.45. Plugging this value in any of the equations gets you s=0.35. So a shark eraser costs 35 cents and a keychain costs 45 cents.  Therefore, the solution is 35+45= {{{highlight(highlight_green(highlight(80)))}}} cents. Click <a href= /algebra/homework/Matrices-and-determiminant/Cramer’s-Rule.solver?content_action=show_dev>here</a> for a solver and click <a href=/my/Equation-Solver-2.solver?content_action=show_dev>here</a> for a different equation solving solver that uses an alternative method.