Four examiners evaluate certain number of papersin 8 days working 5 hours a day.if 2 examiners evaluate twice the number of papers in 20 days,then how many hours per day should thet work?
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Find the number of papers a single examiner can evaluate in a day:
Let the number of papers evaluated by the 4 examiners be x
Step 1: The four examiners evaluate the following fraction each day(8 day):
x/8
Step 2: The fraction they evaluate in an hour ( they work 5 hours a day)
x/8 ÷ 4 = x/8 × 5 = x/40
Step 3: Each examiner evaluates the following fraction in 1 hour:
x/40 ÷ 4 = x/40 × 1/4 = x/160
Therefore x/160 of the total papers is what each examiner can examine in 1 hour.
If 2 examiners evaluate twice the number of papers in 20 days,then how many hours per day should they work?
To answer this we will need to work backwards:
Twice the work = 2 × x = 2x
Working 20 days that means they will evaluate:
2x/20 in 1 day = x/10 of the papers
If 1 examiner = x/160 in hour,
Then 2 examiners = x/160 × 2 = x/80
The 2 examiners can evaluate x/80 of the papers in 1 hour
Therefore if x/80 is 1 hour, how long will x/10 take:
If x/80 = 1 hour
Then x/10 = 1 hour × x/10 ÷ x/80
= 1 × x/10 ×80/x = 80/10 hours = 8hours
Therefore the examiners will have to work 8 hours per day
Let the number of papers evaluated by the 4 examiners be x
Step 1: The four examiners evaluate the following fraction each day(8 day):
x/8
Step 2: The fraction they evaluate in an hour ( they work 5 hours a day)
x/8 ÷ 4 = x/8 × 5 = x/40
Step 3: Each examiner evaluates the following fraction in 1 hour:
x/40 ÷ 4 = x/40 × 1/4 = x/160
Therefore x/160 of the total papers is what each examiner can examine in 1 hour.
If 2 examiners evaluate twice the number of papers in 20 days,then how many hours per day should they work?
To answer this we will need to work backwards:
Twice the work = 2 × x = 2x
Working 20 days that means they will evaluate:
2x/20 in 1 day = x/10 of the papers
If 1 examiner = x/160 in hour,
Then 2 examiners = x/160 × 2 = x/80
The 2 examiners can evaluate x/80 of the papers in 1 hour
Therefore if x/80 is 1 hour, how long will x/10 take:
If x/80 = 1 hour
Then x/10 = 1 hour × x/10 ÷ x/80
= 1 × x/10 ×80/x = 80/10 hours = 8hours
Therefore the examiners will have to work 8 hours per day
Answered by
12
Answer:
8 hours
Step-by-step explanation:
by using this formula,(m1*d1*h1)/w1=(m2*d2*h2)/w2
by subsitute the given values,we get
m=men,d=days,h=hours,w=work
(4*8*5)/1=(2*20*h)/2*1
because twice the work
sol eq we get 8 hrs as ans
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