Question

A group of students volunteered to finish a task in 25 days .1 Q of students did not come n the work could b completed in 35 days .find original number of students in group were??

Answer 1

Answer:

p=7Q/2

Step-by-step explanation:

Original number of students:

p students to do 1 job in 25 days.

Let r= the rate for 1 student.

pr*25=1

pr*25=1 is the work rate equation for p students.

Lesser number of students:

p-Q students came to do the job and time required was 35 days.

(P-Q)*r*35=1.

The unknowns are p, Q and r

Equate the original number of students and the lesser number of students

pr*25=(P-Q)*r*35

25rp=35rp - 35Qr

Collect like terms

25rp-35rp = -35Qr

Divide both sides by -5

-5rp+7rp=- 7rp

It can be re written as

7rp-5rp=-7Qr

2rp=7Qr

Make p the subject of the formula

p=7Qr/2r

p=7Q/2

p=7Q/2 is the original number of students

-10rp = -35Qr

The system of these two equations can be solved for p. See the THREE unknown

variables, p, r, and Q. You might assume that either r or Q would be a constant.