Question

21. If the cost of 30 packets of 8 pencils each is 600, what is the cost of 25 packets of 12
pencils each?
(a) 725
(b)3 750
(c) 2480
d) 7720
22. A rail journey of 75 km costs $215, How much will a journey of 120 km cost?
(a) 344
(b) 3324
(c) 268.75
(d) none of these
23. The 1st, 2nd and 4th terms of a proportion are 12,21 and 14 respectively. Its third term is
(a) 16
(b) 18
(c) 21
24. 10 boys can dig a pitch in 12 hours. How long will 8 boys take to do 11?
(a) 9 h 36 min (b) 15 h
(c) 6 h 40 min (d) 13 h 20 min​

Answer 1

Answer:

21 b ) 750

22 a) 344

23 d) 8

24 a) 9hr

Step-by-step explanation:

quest 21

cost of 8 pencils = 600/30= 20

cost of 1 pencil = 20/8= 2.5

so cost of 25 packet of 12 pencils = 2.5*25*12 = 750

quest 22

cost of 1km = 215/75= 2.8666

cost of 120km = 120*2.86666... = 343.9999 = 344(approx)

quest 23

a/b = c/d

12/21 = c/14

12*14 / 21

= 8

quest 24 : (not sure)

1boy = 12/10 =1.2

8boy = 1.2*8 = 9hrs approx