11. Hisoblang. a) 7 h 45 min 18 s + 4 h 19 min 48 s; b) 6 h 5 min 21 s − 4 h 37 min 52 s; d) (2 d 15 h + 4 d 17 h) : 4; d) (9 d 2 h − 5 d 4 h) · 3

a) Soniyalarni qo‘shamiz: 18 s + 48 s = 66 s = 1 min 6 s. Minutlarni hisoblaymiz: 45 min + 19 min + 1 min = 65 min = 1 h 5 min. So‘ng: 7 h + 4 h + 1 h = 12 h.

Javob: 12 h 5 min 6 s.

b) Qarz olish uchun 6 h 5 min 21 s = 5 h 64 min 81 s. Endi ayiramiz: 81 s − 52 s = 29 s; 64 min − 37 min = 27 min; 5 h − 4 h = 1 h.

Javob: 1 h 27 min 29 s.

d) Qavs ichida hisoblaymiz: 2 d 15 h + 4 d 17 h = 6 d 32 h = 7 d 8 h. Soatga aylantiramiz: 7 d 8 h = 176 h. Bo‘lamiz: 176 h : 4 = 44 h = 1 d 20 h.

Javob: 1 d 20 h.

d) Ayirish uchun 9 d 2 h = 8 d 26 h deb olamiz. Shunda 8 d 26 h − 5 d 4 h = 3 d 22 h. Ko‘paytiramiz: 3 d 22 h · 3 = 9 d 66 h = 11 d 18 h.

Javob: 11 d 18 h.