29.8×15=447 это и есть площадь столовой.
0.9х+4.55=1.5÷0.3
0.9х+4.55=5
0.9х=5-4.55
0.9х=0.45
х=0.45÷0.9
х=0.5
(3 5/6 - 1 2/15) х 5/9 +((1/20 + 24/100) х 8 1/3 - 1 1/6) х 2 =
1)3 5/6 - 1 2/15 = 23/6 - 17/15 = 115/30 - 34/30 = 81/30 = 2 21/30 = 2 7/10.
2) 2 7/10 х 5/9 = 81/30 х 5/9 = 9/6 = 1 1/2.
3) 1/20 + 24/100 = 5/100 +24/100 = 29/100.
4) 29/100 х 8 1/3 = 29/100 х 25/3 = 29//12 = 2 5/12.
5)2 5/12 - 1 1/6 = 29/12 - 7/6 = 29/12 - 14/12 = 15/12 = 1 3/12 = 1 1/4.
6) 1 1/4 х 2 = 5/4 х 2 = 10/4 = 2 2/4 = 2 1/2.
7)1 1/2 + 2 1/2 = 4.
56 = 2 * 2 * 2 * 7 70 = 2 * 5 * 7
НОК (56 и 70) = 2 * 2 * 2 * 5 * 7 = 280 - наименьшее общее кратное