Acompany has two types of machines, type r and type s. operating at a constant rate, a machine of type r does a certain job in 36 hours and a machine of type s does the same job in 18 hours. if the company used the same number of each type of machine to do the job in 2 hours, how many machines of type r were used?
a. 3b. 4c. 6d. 9e. 12

C. 6

Therefore, 6 machine R was used.

Step-by-step explanation:

Given;

Time taken for machine R = 36 hours

Time taken for machine S = 18 hours

The fraction of work completed by machine R and S in 1 hour is ;

R = 1/36

S = 1/18

Let n represent the number of each type of machine used to do the job.

Time taken for n machine R and S is 2 hours.

The fraction of job completed by n Machine R and S is;

n(R +S) = 1/2

Since R = 1/36 and S = 1/18

n(1/36 + 1/18) = 1/2

n = 1/2/(1/36 + 1/18)

n = 6

Therefore, 6 machine R was used.

change of stock price/initial stock price on friday * total stock value = change of stock value

0.89/73.73 *x = 42.72

x=3539.04 = total stock value at initial stock price on friday .

total stock value at initial stock price on friday/ initial stock price on friday = number of shares

3539.04/73.73 = 48 shares

they own 48 shares of this stock