To add these fractions, first find the lowest common multiple of their denominators. The first few multiples of 5 are [5, 10, 15, 20, 25, 30, 35, 40, 45, 50] and the first few multiples of 9 are [9, 18, 27, 36, 45, 54, 63, 72, 81, 90]. The first few multiples they share are [45, 90] making 45 the smallest multiple 5 and 9 share.

Next, convert the fractions so each denominator equals the lowest common multiple:

\( \frac{3 x 9}{5 x 9} \) + \( \frac{5 x 5}{9 x 5} \)

\( \frac{27}{45} \) + \( \frac{25}{45} \)

Now, because the fractions share a common denominator, you can add them:

\( \frac{27 + 25}{45} \) = \( \frac{52}{45} \) = 1\(\frac{7}{45}\)

Betty scored 94% on the test meaning she earned 94% of the possible points on the test. There were 200 possible points on the test so she earned 200 x 0.94 = 188 points. Each question is worth 4 points so she got \( \frac{188}{4} \) = 47 questions right.

The factors of a number are all positive integers that divide evenly into the number. The factors of 20 are 1, 2, 4, 5, 10, 20.

If the tiger has consumed 70 pounds of food in 5 days that's \( \frac{70}{5} \) = 14 pounds of food per day. The tiger needs to consume 168 - 70 = 98 more pounds of food to reach 168 pounds total. At 14 pounds of food per day that's \( \frac{98}{14} \) = 7 more days.

45% of the water consumption is industrial use and 14% is personal use so (45% - 14%) = 31% more water is used for industrial purposes. 20,000 gallons are consumed daily so industry consumes \( \frac{31}{100} \) x 20,000 gallons = 6,200 gallons.