Question 1207183
<br>
Let x be the cost in cents of each lollipop
Then x+15 is the cost in cents of each chocolate<br>
Since the chocolates and lollipops were in the ratio 7:4, the ratio of the costs of the chocolates to the cost of the lollipops was {{{(7(x+15))/(4(x))}}}.<br>
That ratio of costs was 5:2<br>
{{{(7(x+15))/(4(x))=5/2}}}
{{{14(x+15)=20(x)}}}
{{{14x+210=20x}}}
{{{6x=210}}}
{{{x=35}}}<br>
From the given information, we know...
cost of each lollipop: x = 35 cents
cost of each chocolate: x+15 = 50 cents<br>
But the question asks us to find the number of lollipops she bought -- and there is no information given that allows us to answer that question.  We only know that the chocolates and lollipops were in the ratio 7:4.  So, for example...<br>
7 chocolates and 4 lollipops
cost of chocolates 7(50) = 350, cost of lollipops 4(35) = 140, ratio of costs 350:140 = 5:2<br>
35 chocolates and 20 lollipops
cost of chocolates 35(50) = 1750, cost of lollipops 20(35) = 700, ratio of costs 1750:700 = 5:2<br>
etc....<br>
Another problem (from the same student maybe) for which we can't find the answer....<br>