Answer:
Change 45 min to .75 hrs
Distance = speed * time
Train A's distance = 55(t+.75)
Train B's distance = 70t
The equation
D(t) = 70t + 55(t+.75)
The first number in the couplet is the distance along the x-axis (i.e. distance from the y-axis). We can read 0.8 from the graph.
The second number is the distance along the y-axis (i.e.distance from the x-axis). We can read 6.7 from the graph.
So approximately, we have the point as (0.8, 6.7).
Round the numbers to the nearest integer and you'll get the required answer choice.
First, let me do the Mathematical part of that, and then I shall explain the theory behind it.
Mathematical part:
We are going to multiply 513 with 46. So the two partial products that we are going to choose are 40 and 6.
Multiply 513 with 6 first.
513
x46
--------------------------
18 (as 6*3 = 18)
60 (as 6*10 = 60; In 513, the digit at tenths place is 1, so 1*10=10)
3000 (as 6*500 = 3000; In 513, 5 is at hundredth place, so 5*100=500)
120 (as 40*3 = 120; since 4 is at the tenth place, so 4*10=40)
400 (as 40*10 = 400)
20000 (as 40*500 = 20000)
--------------------------
23598 (Add all of them)
Theory:
As you can see above that we have chosen the two partial products individually which are 6 and 40. Since 4 in 46 is in tenth place, we have to consider it 40 (since 4*10 = 40). One by one, we first multiply 6 with 513. Then we move to the tenth place, and multiply 513 with 40. At the end, we have added all the results we found after multiplication.
Check: If we check the multiplication result by using the calculator, we would get the same result (23598).
Another Method (instant):
513 * (40+6) = (513*40) + (513*6) = 23598.
Answer:
$4.72
Step-by-step explanation:
16.79+28.49=45.28
50-45.28=4.72
