you would change the denominators to the least common multiple, in this case, 12. then you would change the fractions to 8/12, 14/12, and 7/12. you would add those, and get 29/12. divide 29 by 12, and get 2. add the rest to get 2 5/12.
The bike will cost $481.50
because
10% off of 500 is 50
so 500 - 50 = 450
Now include the sales tax which is
450 * 0.07 = 31.5
Now add the two totals to get
$481.50
The temperature would be (21.5 + 6.25) which is 27.75
C. $135, 1/4 of 60 is 15 and add that on top of 60x2
