1989 AJHSME Problems/Problem 10

Problem

What is the number of degrees in the smaller angle between the hour hand and the minute hand on a clock that reads seven o'clock?

$\text{(A)}\ 50^\circ \qquad \text{(B)}\ 120^\circ \qquad \text{(C)}\ 135^\circ \qquad \text{(D)}\ 150^\circ \qquad \text{(E)}\ 165^\circ$

Solution

The smaller angle makes up $5/12$ of the circle which is the clock. A circle is $360^\circ$, so the measure of the smaller angle is \[\frac{5}{12}\cdot 360^\circ = 150^\circ \rightarrow \boxed{\text{D}}\]

See Also

1989 AJHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 9
Followed by
Problem 11
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