Question

In a village, four blood camps were organized. People of the village donated their blood. If the average number of blood bottles donated in camp I and II is 30, in camp II and III is 40 and in III and IV Camp is 60. The difference in the number of blood bottles donated in camp I and camp IV is 20. Find the number of bottles donated in camp I. (Camp I > Camp IV)
1. 35
2. 60
3. 65
4. 75
5. 85

Answer 1

Correct Answer - Option 2 : 60

Given:

The average number of blood bottles donated in camp I and Camp II = 30

The average number of blood bottles donated in camp II and Camp III = 40

The average number of blood bottles donated in camp III and Camp IV = 60

Formula used:

Average = Sum of all the observation/ Total number of observation

Calculation:

Total number of bottles donated in camp I and camp II = 60

i.e. I + II = 60      ….(1)

Total number of bottles donated in camp II and camp III = 80

 i.e. II + III = 80      ….(2)

Total number of bottles donated in camp III and camp IV = 120

i.e. III + IV  = 120

⇒ III = 120 – IV        ….(3)

Put equation (3) in (2)

⇒ II + 120 – IV = 80

⇒ II – IV = - 40

⇒ II = - 40 + IV         ….(4)

Put equation (4) in equation (1)

⇒ I – 40 + IV = 60

I + IV = 100     ….(5)

I - IV =   20       ….(6)

From (5) and (6)

⇒ IV = 40

⇒ I = 60

∴ 60 bottles were donated in camp I.