scooby made 70 percent on his science test. if he got 21 problems correct how many problems are on the test

1 answer:

7 0

Since the score is 21 out of an unknown number, and the percantage is 70%, you set .7 equal to the score (21/x), and solve for x

.7 = 21/x

Multiply both sides by x

.7x = 21

Divide both sides by .7

x = 30

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$= \{ {( \frac{ \sqrt{3} }{2}) }^{2} { \cos }^{2} \theta \} - \{ {( \frac{ \sqrt{3} }{2} )}^{2} { \sin }^{2} \theta \} \\ \\ = \frac{3}{4} { \cos }^{2} \theta - \frac{3}{4} { \sin}^{2} \theta$