Problema Solution

Lucy and Barbara began saving money the same week. The table below shows that models for the amount of money Lucy and Barbara have saved after x weeks. After how many weeks will they have the same amount of money saved?

Lucy's Savings: f(x)=10x+5 Barbara's Savings: g(x)=7.5x+55

Answer provided by our tutors

let 'a' be the number of weeks after they have the same amount of money then


f(a) = g(a)


10a + 5 = 7.5a + 55


by solving the equation we find


a = 20 weeks


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After 20 weeks Lucy's and Barbara's savings will be the same.


also, if we draw the graph for the functions f(x)=10x+5 and g(x)=7.5x+55 the intersection on the graphs gives the solution


click here to see the graph of the functions

https://www.quickmath.com/webMathematica3/quickmath/graphs/equations/advanced.jsp#c=plot_advancedgraphequations&v1=y+%3D7.5x%2B55&v2=y+%3D10x%2B5+&v7=x&v8=y&v9=0&v10=30&v11=0&v12=300