Mark has $\frac{3}{4}$ of a dollar and Carolyn has $\frac{3}{10}$ of a dollar. Together they have
(A) $\$ 0.90$
(B) $\$ 0.95$
(C) $\$ 1.00$
(D) $\$ 1.10$
(E) $\$ 1.05$
Solution 1

Mark has $\frac{3}{4}$ of a dollar, or 75 cents.

Carolyn has $\frac{3}{10}$ of a dollar, or 30 cents.

Together, they have $75+30=105$ cents, or $\$ 1.05$.

Solution 2

Since Mark has $\frac{3}{4}$ of a dollar and Carolyn has $\frac{3}{10}$ of a dollar, then together they have $\frac{3}{4}+\frac{3}{10}=\frac{15}{20}+\frac{6}{20}=\frac{21}{20}$ of a dollar.

Since $\frac{21}{20}$ is equivalent to $\frac{105}{100}$, they have $\$ 1.05$.

ANSWER: (E)