3) Maurice has a pet hamster. In October he spent $ 13.68 on hamster food
$ 7.89 on wood shavings
$ 21.14 on a new hamster wheel.
About how much money did he spend on his hamster? Estimate by rounding each amount to
the nearest dollar.
Exactly how much did he spend on his hamster in October?

$43

Step-by-step explanation:

13.68= about 14

7.89= about  8

21.14=  about 21

So, 14+8+21=43

Let a represent the # of adults and s the # of students attending.

Since 938 people attended, a + s = 938, or s = 938 - a

Ticket sales to adults brought in $2.00(a) and ticket sales to students brought in $0.75s.  We must solve for a and s.

Let's do that via substitution of 938 - a for s:

$2.00a + $0.75(938-a) = $1109   (which was the total sales revenue)

Then 2.00a + 0.75(938) - 0.75a = 1109.  Combining like terms, we get:

1.25a = 1109 - 0.75(938), or  

1.25a = 1109 - 703.5, or:

1.25 a = 405.50

Dividing both sides by 1.25, we get:

a = 324.4

Let a represent the # of adults and s the # of students attending.

Since 938 people attended, a + s = 938, or s = 938 - a

Ticket sales to adults brought in $2.00(a) and ticket sales to students brought in $0.75s.  We must solve for a and s.

Let's eliminate s.  Solve a + s = 938 for a:  a = 938 - s.

Then $2(938 - s) + $0.75s = $1109.

This simplifies to $1876 - $2s + $0.75s = $1109, or

$1186 - $1109 = $1.25s.  Solving for s, we get s = 613.6

I did this problem twice, once by eliminating a and once by eliminating s.  Both times the number of students came out to be 613.6 and the number of adults 324.4.  This makes zero sense, since such a count MUST be integer.

Would you please double check to ensure that you've copied down this problem correctly.  Thank you.