Question 250842
This question requires you to set up 2 equations and 2 unknowns.The first equation I call the "number" equation because it gives you the actual number of items. The second equation, I call the "value" equation because it gives you the total value of the items. Let C = cone and S = sundae.
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step 1 - write the equations:
(i) {{{ C + S = 172}}}
(ii) {{{110C + 235S = 29420}}}
I generally don't use decimals and dollar signs on my value equation.
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step 2 - multiply the first equation by -110.
(iii) {{{ -110C - 110S = - 18920}}}
(iv) {{{110 + 235S = 29420}}}
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step 3 - add down to eliminate C.
(v) {{{125S = 10500}}}
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step 4 - Solve for Sand then C. S = 84. C = 88.
88 cones were sold.