JOINT VARIATION AND COMBINED VARIATION Multiple Choice: Choose the letter that correspond to the correct answer.

1. Which of the following is the same as direct variation with two or more variables?
a. combined variation
b. inverse variation
c. joint variation
d. combined variation

2. What is the equation of variation if p varies jointly as q and r, & the constant of variation is 4. a. p = 4qr
b. q = 4pr
c. 4 = pqr
d. r = 4pq

For numbers 3-5 The area of a rectangle varies jointly as the length and the width, whose A = 72 sq. cm when l = 3 cm & w = 2 cm.

3. What is the equation of variation?
a. A = kl/w
b. k = Alw
c. A = l/w
d. A = klw

4. What is the constant of variation?
a. 12
b. 10
c. 8
d. 14

5. What is the area of rectangle if the length is 15 cm & whose width is 3 cm?
a. 450 sq. cm
b. 540 sq. cm
c. 145 sq. cm
d. 375 sq. cm

6. It is a situation where a variable depends on two (or more) other variables, and varies directly with some of them & varies inversely with others.
a. direct variation
b. combined variation
c. inverse variation
d. joint variation

7. What is the constant of variation k if a varies directly as the square of b & inversely as c, and a = 4 when b = 4 and c = 8? a. 4 b. 3 c. 2 d. 1 For numbers 8-10 In Tanza National Trade School, the number of girls g varies directly as the number of boys b and inversely as the number of teachers t. When there were 50 girls, there were 20 teachers and 10 boys. 8. What is the equation of variation?
a. g = kb/t
b. g = kbt
c. g = .b/t
d. k = gbt

9. What is the constant of variation?
a. 140
b. 120
c. 100
d. 80

10. How many girls were there when there were 30 boys & 60 teachers?
a. 70
b. 40
c. 60
d. 50​