Sat Math Strategies Mini Quiz Worksheet With Answer Key (Page 3 of 4) in pdf

Sat Math Strategies Mini Quiz Worksheet With Answer Key Page 3

SAT Math Strategies Mini Quiz

Strategy: work with the answers. Use the answers to try various values for p.

Using answer E, p = 450, and q = p/10 = 45, so the sum of p and q is 495. Answer

E is correct. Note that if you start with answer A here, you will ﬁnd that the sum

of p and q is way oﬀ (44 instead of what we want: 495). Since the answers are in

order, skip one or two answers before trying the next one. In this case, try C or D

next.

Math Teacher Solution: Set up two equations:

p + q = 495

and

= q

Substituting the second equation into the ﬁrst, we get p + p/10 = (1.1)p = 495 so

that p = 450.

Strategy: work with the answers. Use the answers to try choices for the

number of green marshmallows. If there are 9 green marshmallows (answer C),

then there are 6 + 9 = 15 total marshmallows, so the probability of choosing a

purple one is 6/15 = 2/5 > 1/3, so answer C is incorrect. We need more green

marshmallows to get a lower probability for choosing a purple marshmallow, so we

try an answer to the right. If there are 12 green marshmallows (answer D), then

there are 6 + 12 = 18 total marshmallows, so the probability of choosing a purple

one is 6/18 = 1/3. Answer D is correct.

Math Teacher Solution: Let x be the number of green marshmallows. Then,

6 + x is the total number of marshmallows. The probability of choosing a purple

marshmallow is the number of purple marshmallows (6) divided by the total number

of marshmallows (6 + x). So, we need:

6 + x

Cross-multiplying, 18 = 6 + x so that x = 12.

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Sat Math Strategies Mini Quiz Worksheet With Answer Key Page 3