(3,09:1/40 - 32,3:17/50) . 1/4 + 0,69 . 1/3

Решим пример по действиям:

1) 3,09 : 1/40 = 309/100 * 40 = (309 * 40)/100 = (309 * 4)/10 = 1236/10;

2) 32,3 : 17/50 = 323/10 * 50/17 = (323 * 50)/(10 * 17) = (323 * 5)/17 = 19 * 5 = 95;

3) 1236/10 - 95 = 1236/10 - 950/10 = (1236 - 950)/10 = 286/10;

4) 286/10 * 1/4 = 286/40 = 143/20;

5) 0,69 * 1/3 = 69/100 * 1/3 = 69/300 = 23/100;

6) 143/20 + 23/100 = 1430/200 + 46/200 = (1430 + 46)/200 = 1476/200 = 738/100 = 7,38.

Ответ: 7,38.