The grocery receipt shows the cost of three items before tax is added. When a $5 \%$ tax is added to the cost of the items, what is the total cost for the three items?
(A) $\$ 15.16$
(B) $\$ 15.08$
(C) $\$ 15.22$
(D) $\$ 15.75$
(E) $\$ 15.38$

| Sponge | $\$ 4.20$ |
| :--- | ---: |
| Shampoo | $\$ 7.60$ |
| Soap | $\$ 3.20$ |

Part B: Each correct answer is worth 6.
Before adding tax, the combined cost of the three items is $\$ 4.20+\$ 7.60+\$ 3.20=\$ 15.00$.

The $5 \% \operatorname{tax}$ on $\$ 15.00$ is $0.05 \times \$ 15.00=\$ 0.75$, and so the total cost of the three items, after tax is added, is $\$ 15.00+\$ 0.75=\$ 15.75$.

Note that we could have calculated the $5 \%$ tax on each individual item, however doing so is less efficient than calculating tax on the $\$ 15.00$ total.

ANSWER: (D)