Dexter

Dexter spent 1 2/3 hours working on his history homework and another 2 1/5 hours working on his math homework.
How many hours did Dexter spend working on the two homework?

Correct answer:

t =  3 ¹³⁄₁₅ = 58/15 h

Step-by-step explanation:

$$\begin{gathered} t_1=1\frac{2}{3}=1+\frac{2}{3}=\frac{1\cdot 3+2}{3}=\frac{3+2}{3}=\frac{5}{3}\doteq 1.6667\text{h} \\ {t}_2=2\frac{1}{5}=2+\frac{1}{5}=\frac{2\cdot 5+1}{5}=\frac{10+1}{5}=\frac{11}{5}=2.2\text{h} \\ t=t_1+t_2=\frac{5}{3}+\frac{11}{5}=\frac{25}{15}+\frac{33}{15}=\frac{25+33}{15}=\frac{58}{15}=\frac{58}{15}\text{h}=3\frac{13}{15}\text{h}=3.8667\text{h} \end{gathered}$$

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