+4 Peter delivered 210 food orders in a week. For every order that was delivered on time, he earned $3.50. For every order that was delivered late, he would not earn any money and would have to pay a fine of $4.30 instead. He received $532.20 at the end of the week. How many orders were delivered on time?
+157 Let the number of orders that were delivered on time be \(a\).
\(3.5a - 4.3(210-a) = 532.2\)
\(3.5a-903+4.3a=532.2\)
\(7.8a-903=532.2\)
\(7.8a=1435.2\)
\(a=184\)
Now we should check our answers:
If \(184\) orders were delivered on time, Peter would have
\(184\times$3.5=$644\).
If there were \(184\) orders that were on time, there were
\(210-184=26\) late orders.
We should now subtract
\(26\times$4.3=$111.8\)
from Peter's \($644\).
\($644-$111.8=$532.2\)
\(184 \) orders were delivered on time.
