Answer:
associative property with respect to addition and subtraction
3+[7+(-4)]=(3+7)+(-4)
3+[7-4]=10+(-4)
3+3=10-4
6=6
Step-by-step explanation:
i hope it will help you
Answer: Time it took her to get to the school is 0.6 hours
The distance of the school from their home is 27 miles
Step-by-step explanation:
Mrs Dang drove her daughter to school at the average speed of 45 miles per hour.
Let x miles = distance from the school to their home.
Distance = speed × time
Time = distance / speed
Time used in going to school will be
x/45
She returned home by the same route. This means that distance back home is also x miles.
She returned at an average speed of 30 miles per hour.
Time used in returning home from school will be x/30
x/45
If the trip took one half hour, then the time spent in going to school and the time spent in returning is 1 1/2 hours = 1.5 hours. Therefore
x/30 + x/45 = 1.5
(15x + 10x) /450 = 1.5
15x + 10x = 450 × 1.5 = 675
25x = 675
x = 675/25 = 27
Time it took her to get to the school will be x/45
= 27/45 = 0.6 hours
<span>So we need to see how does the decimal point change it's place in the quotient when we divide any number by increasing powers of 10. Lets start with number 1. The decimal point is: 1.0 and when we divide by 10^1=10 we get 1/10=0.1. The decimal point has moved one place to the left. Now lets divide 1 by 10^2 and we get 1/100=0.01. Again, the decimal point has moved one more place to the left. Now: 1/10^3 = 1/1000 = 0.001. Next would be 0.0001, next one would be 0.00001 and so on. </span>
3,500-680= 2,820 feet
2,820+725= 3,545 feet
ANSWER:
3,545 feet
