Answer:
80 questions
Step-by-step explanation:
You can write a proportion to solve this. A proportion is an equation that sets two ratios equal.
The first ratio is 60/x where x is the number of questions. The second ratio is 75/100. This is the percent you got on the test. Cross multiply to sole for x.

Answer:
c) parabola and circle: 0, 1, 2, 3, 4 times
d) parabola and hyperbola: 1, 2, 3 times
Step-by-step explanation:
c. A parabola can miss a circle, be tangent to it in 1 or 2 places, intersect it 2 places and be tangent at a 3rd, or intersect in 4 places.
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d. A parabola must intersect a hyperbola in at least one place, but cannot intersect in more than 3 places. If the parabola is tangent to the hyperbola, the number of intersections will be 2.
If the parabola or the hyperbola are "off-axis", then the number of intersections may be 0 or 4 as well. Those cases seem to be excluded in this problem statement.
6 6/15 because if you multiply the mixed number first then multiply the fraction
It is a distribution that always has a constant and equal probability:)