Alon and his friend Marna own a chimney sweep service company. Working together, they can clean a 20-foot chimney in 1 Five-sevenths hours. If it takes Kalon 4 hours to clean a 20-foot chimney by himself, how long does it take Marna to clean the same size chimney by herself?

3 hours

Step-by-step explanation:

Given that:

Time taken by Kalon = 4 hours

Time taken by Marna =?

Time taken if the work together = 1 5/7 hours

Kalon's rate = 1/ time =. 1/4

Kalon + Marna = 1 ÷ 1 5/7 = 7/12

Hence,

Marna's rate = 7/12 - 1/4

Marna's Rate = (7 - 3) / 12 = 4/12 = 1/3

Marna's rate = 1/3

Hence, time it takes Marna = reciprocal of rate = 1÷ 1/3 = 1 * 3/1 = 3 hours

a. 3/4 ÷ 1/8 = 6

step-by-step explanation:

in the question, the number line represents 3/4 divided into 6 equal units. each arrow represents a unit and there are a total of six arrows.

the size of each unit is 1/8 as shown.

showing that 1/8 divides 3/4 into 6 divisions:

3/4 ÷ 1/8

= 3/4 x 8/1

= 3/1 x 8/4

= 3 x 2

= 6

hence, the number line represents six divisions given by 3/4 ÷ 1/8.

answer: c

(2, -4)

goes 7 to the

(9, 4)

easy