Unitary Method
- If the cost of 1/4 th of kg is Rs. 0·60, then what is the cost of 200 gm ?
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As we know that ,
∴ 1 kg = 1000 grams⇒ 1 kg = 1000 × 1 = 250 grams 4 4
∵ The cost of 250 grams = 60 paise
Correct Option: B
As we know that ,
∴ 1 kg = 1000 grams⇒ 1 kg = 1000 × 1 = 250 grams 4 4
∵ The cost of 250 grams = 60 paise∴ The cost of 200 grams = 60 × 200 250
Thus , The cost of 200 grams = 48 paise
- The cost of 2 tables is equal to the cost of 5 chairs. If the difference of the cost of one table and one chair is Rs. 1200, then the cost of one chair is —
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Let the cost of the table be Rs. p and the cost of the chair = Rs. q
From Ist condition, 2p = 5qp = 5q 2
From IInd condition,
p – q = Rs. 12005q – q = 1200 2
Correct Option: C
Let the cost of the table be Rs. p and the cost of the chair = Rs. q
From Ist condition, 2p = 5qp = 5q 2
From IInd condition,
p – q = Rs. 12005q – q = 1200 2 3q = 1200 2
⇒ q = Rs. 800
Hence , the cost of one chair is Rs. 800 .
- When a 192 meters long rod is cut down into small pieces of length 3·2 meters each. Then how many pieces are available ?
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Given :- Total length of long rod = 192 metres
And Total length of small rod = 3·2 metresNow , No. of pieces = Total length of long rod Total length of each small rod Correct Option: D
Given :- Total length of long rod = 192 metres
And Total length of small rod = 3·2 metresNow , No. of pieces = Total length of long rod Total length of each small rod No. of pieces = 192 = 60 3·2
- If 12 men or 18 women can do a piece of work in 14 days, then how long will 8 men and 16 women take to finish the work ?
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12 men ≡ 18 women
⇒ 1 man ≡ 18/12 women ≡ 3/2 women
∴ 8 men ≡ (3/2) x 8 = 12 women
∴ 8 men + 16 women = 12 women + 16 women = 28 women
∵ 18 women can do the work in 14 days .
∴ 1 woman can do the same work in (14 x 18) days.Correct Option: A
12 men ≡ 18 women
⇒ 1 man ≡ 18/12 women ≡ 3/2 women
∴ 8 men ≡ (3/2) x 8 = 12 women
∴ 8 men + 16 women = 12 women + 16 women = 28 women
∵ 18 women can do the work in 14 days .
∴ 1 woman can do the same work in (14 x 18) days.
∴ 28 women will do the same work in (14 x 18)/28 days.
∴ Required number of days = (14 x 18)/28 = 9 days
- 25 men can reap a field in 20 days. when should 15 men leave the work, if the whole field is to be reaped in 371/2 days after they leave the work ?
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Let 15 men work for m days.
Work done in 1 days = m/20
Remaining work = (1 - m/20)
25 men's 1 days work = 1/20
1 man's 1 days work = (1/20) x (1/25) = 1/500
10 men's 1 days work = 10/500 = 1/50
10 men's 75/2 days work = (1/50) x (75/2) = 75/100 = 3/4
∴ (1 - m/20) = 3/4Correct Option: A
Let 15 men work for m days.
Work done in 1 days = m/20
Remaining work = (1 - m/20)
25 men's 1 days work = 1/20
1 man's 1 days work = (1/20) x (1/25) = 1/500
10 men's 1 days work = 10/500 = 1/50
10 men's 75/2 days work = (1/50) x (75/2) = 75/100 = 3/4
∴ (1 - m/20) = 3/4
⇒ m/20 = 1/4
⇒ m = (1/4) x 20 = 5
Clearly, 15 men leave after 5 days.
