Question

Activity 2
Aim: To make a model to demonstrate the mechanism of breathing
Materials Required - Wide plastic bottle (1), Y-shaped glass/plastic
tube fixed in a rubber cork, balloons (2). thin rubber or plastic
sheet, thread
Method: Follow the steps given below.
Fix two deflated balloons to the forked end of the Y-tube.
Insert the Y-tube having balloons into the rubber cork.
Fix the rubber cork into the mouth of the bottle and make it airtight.
Working
Now, release the rubber sheet gently and observe the balloons.
Balloons get deflated.
Science-1
122
Tie a thin plastic sheet at the open base of the bottle with a strong thread rubber band
Pull the rubber sheet downward gently and observe the balloons. Balloons graduallye explain in hindi​

Answer 1

A can finish work in 18 days.

It means A can do the work in one day = 1/18 part

B can finish it in 15 days.

It means B can do the work in one day = 1/15 part

B worked alone for 10 days and then left the job

Thus in 10 days B has completed part of work =

1/15 × 10 = 10/15 part or 2/3 part of work

Remaining work left = 1 - 2/3 = 1/3 part of work remaining

A can do 1/18 part in one day

Therefore 1/3 part will be completed by him

= 1/1/18 × 1/3

= 1/3 × 18/1

= 18/3 days

= 6 days

A alone will complete the work in 6 days

Answer : A alone will finish the work in 6 days

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