15.

(a) 30030

(b) (i) 4

(ii) 525

(iii) 4

16.

(a) 15

(b) 1

(c) 108

17.

20, 21

18.

10 a.m.

19.

(a) 1101 hr

(b) 20

(c) 12

20.

12, 7

21.

1030 hr

21.

(a) -5.919

(b) -13

(c) -1/14

21.

(d) 1/4

(b)

523/1750

24.

0.4

25.

(a) 0.0284 (3 s.f.)

(b) 12.396 (3 d.p.)

(c)(i) 22.78 (2 d.p.)

(ii) 6.87 (3 s.f.)

26.

(a) 2 1/9

(b) -50

27.

271.358 (3 d.p.)