__Answers :__

**1). Answer: d) **

Total work = men*days

Total units of work = 25*16 = 400 units

Work done in 4 days = 25*4 = 100 units

Remaining work = 400 – 100 = 300 units

Let the number of men left after 4 days be x,

According to the question,

300/15 = 25 – x

20 = 25 – x

X = 5 men

After 4 days from the start of the work, 5 men left the job.

**2). Answer: a) **

Total work = (men (or) women)*days

Work equal,

(10w + 6m)*5 = (7w + 8m)*6

50w + 30m = 42w + 48m

8w = 18m

4w = 9m = > 1w = (9/4) m

10w + 6m = 10*(9/4) m + 6m = (57/2) m

12w + 5m = 12*(9/4) m + 3 m = 30 m

**Women days**

(57/2) 5

30 ?

(57/2)*5 = 30x

X = (57/2)*(5/30) = 4 9/12 = 4 ¾ days

**3). Answer: c) **

Total work = men * days

Total work = 20*12 = 240

6 days work = 20*6 = 120

Remaining work = 240 – 120 = 120 work

Now, the total men = 20 – 5 = 15 men

Remaining work can be completed in,

= > 120/15 = 8 days

Remaining work gets completed in 8 days.

**4). Answer: b) **

1/12 + 1/16 + 1/C = 3/16

1/C = (3/16) – (1/12 + 1/16)

(1/C) = (3/16) – (7/48) = 1/24

C can do it in 24 days.

Efficiency of A, B and C = (1/12) : (1/16) : (1/24) = 4 : 3 : 2

9’s = 4500

1’s = 500

The share of C = Rs. 1000

**5). Answer: d) **

**Shortcut:**

Men women days

4 7 49

6 14 ?

Required days = (4*7*49)/(56 + 42) = (4*7*49)/98

= > 14 days

**(Or)**

4 men = 7 women

1 men = (7/4) women

6 m + 14 w = 6*(7/4) w + 14 w = 49/2 w

Women days

7 49

49/2 ?

= > (7*49*2)/49 = 14 days

**6). Answer: d) **

Manohar and Ragu’s one day work = (1/15) + (1/18) = 11/90

Manohar and Ragu’s 6 day work = (11/90)*6 = 11/15

Remaining work 4/15 done by Manohar and Ranjith

Manohar and Ranjith finished it in 1 1/3 days

(4/15)*(Manohar + Ranjith)’s whole work = (4/3)

(Manohar + Ranjith)’s whole work = (4/3)*(15/4) = 5 days

Ranjith’s one day work = (1/5) – (1/15) = 2/15

Ranjith alone can complete the work in 7 ½ days

**7). Answer: c) **

A, B and C together complete the work in = 4 32/37 days = 180/37 days

(A + B + C)’s one day work = 37/180

B’s one day work = 1/18

C’s one day work = 1/15

A’s one day work = (37/180) – (1/18 + 1/15)

= > 37/180 – 11/90 = 15/180 = 1/12

A can take to complete the work alone in 12 days

**8). Answer: c) **

A can complete 3/5^{th} of the work = 6 days

A can complete the whole work in = 6*(5/3) = 10 days

B can complete 2/7^{th} of the work = 4 days

B can complete the whole work in = 4*(7/2) = 14 days

(A + B)’s one day work = (1/10) + (1/14) = 24/(10*14) = 6/35

A and B together can complete the work in, 35/6 = 5 5/6 days

**9). Answer: b) **

Efficiency ratio = > Q : P = 140 : 100 = 7 : 5

Days ratio = > Q : P = 5 : 7

P can do a piece of work in 21 days

7’s = 21 = > 1’s = 3

So Q can complete the work in 15 days

= > 1/21 + 1/15

**= **> 36/(21*15) = 4/35

P and Q together can complete the work in 35/4 = 8 ¾ days

**10). Answer: b) **

(x + 3) person can do the work in = (x – 5)

(x – 3)*x = (x + 3) (x – 5)

X^{2} – 3x = x^{2} – 5x + 3x – 15

X = 15

**Person days**

12 15

20 ?

(12*15) = 20*y

Y = 180/20 = 9 days