we know that
Rolls of pennys and dimes consist of 50 coins each
Rolls of nickels and quarter consist of 40 coins each
so
Step 1
Find how many rolls of penny Darla has
Divide the number of coins by 50
472/50=9.44
round to the nearest whole number
9 rolls
step 2
Find how many rolls of nickels Darla has
Divide the number of coins by 40
319/40=7.9
7 rolls
step 3
Find how many rolls of dimes Darla has
Divide the number of coins by 50
436/50=8.72
8 rolls
step 4
Find how many rolls of quarters Darla has
divide the number of coins by 40
271/40=6.78
6 rolls
step 5
Adds the number of rolls
9+7+8+6=30 rolls
Remember that in this problem rounding is down