Question

Mary bought some bagels and some rolls. The bagels cost .40$ each and the rolls cost .25$. If she spent 3.90$ in all for 12 items, how many of each did she buy?

Answer 1

Answer:

There are 6 bagels and 6 rolls.

Step-by-step explanation:

Let the number of bagels be 'b' and rolls be 'r'.

Given:

Cost of 1 bagel = $0.40

Cost of 1 roll = $0.25

Number of items = 12

Total cost of the 12 items = $3.90

Now, number of items is the sum of the bagels and rolls. So,

$b+r=12$ ---------- (1)

Now, total cost of the items is the cost of 'b' bagels plus the cost of 'r' rolls.

So, total cost in equation form is:

$0.40b+0.25r=3.90$ --------- (2)

Now, multiplying equation (1) by -0.25 and adding the result to equation (2), we get:

$b\times -0.25 +r\times -0.25=12\times -0.25\\\\-0.25b-0.25r=-3\\0.40b+0.25r=3.90\\-----------\\0.15b=0.90\\\\b=\frac{0.90}{0.15}=6$

So, number of bagels is 6.

Number of rolls, $r=12-b=12-6=6$

So, there are 6 bagels and 6 rolls.