a charter bus travels 210 miles in 3 1/2 hours. assume the distance traveled is directly proportional to the time traveled. write and solve a direct variation equation to find how far the bus travel in 6 hours.
The constant of variation is 60 miles.
Direct variation formula: y = kx
y = 210
x = 3 1/2 miles
k = ?
k = y/x
k = 210 / 3 1/2 miles
convert mixed fraction into a simple fraction
3 1/2 = (32+1)/2 = 7/2
k = 210 ÷ 7/2
Remember the rule of dividing fractions: multiply the 1st fraction by the reciprocal of the 2nd fraction.
1st fraction = 210 ⇒ 210/1
2nd fraction = 7/2 ⇒ reciprocal = 2/7
k = 210/1 2/7 = (2102)/(1*7) = 420/7 = 60
The constant of variation is 60 miles.
To check:
y = kx
y = 60 (3.5)
y = 210 miles
We set up an equation: 210 miles/ (3 1/2 hours)= ? miles/ 6 hours
Cross multiply:
? miles 3 1/2 hours= 210 miles 6 hours
⇒ ? miles= 210 miles* 6 hours/ (3 1/2 hours)= 360 miles.
The bus would travel 360 miles in 6 hours~