20ч.55мин=20целых55/60=20целых11/12 ч
1. В
2. Д
3. Г
А3. 4
А4. 3
В1. 6
В2. а, г
<span>6(а+1,5)-2,8а=</span>6а+9-2,8а=3,2а+9
3,2*1,5+9=4,8+9=13,8
1) = 15 * 2 + 361 - 318 = 30 + 361 - 318 = 391 - 318 = 73
2) = 64 * 10 - 549 +324 = 640 - 549 + 324 = 324 +91 = 415
<span>15/(3 12/17+2 5/17)+(4.2-2 3/5)/4 =2 9/10</span>
<span>1)3 12/17+2 5/17=5 17/17=6</span>
<span>2)15:6=2.5</span>
<span>3)4.2-2 3/5=4.2-2.6=1.6</span>
<span>4)1.6:4=0.4</span>
<span>5)2.5+0.4=2.9=2 9/10</span>