Answer:
The last method (Round 13.76 to 14, round 9.8 to 10, and round 16.415 to 16; since 14 + 10 + 16 = 40 and 40 is close to 39.975, her answer is reasonable.)
Step-by-step explanation:
Option 1 is unreasonable because removing the decimal points just changes the whole problem and claims that Harshini rode her bike 1376 kilometers on Monday and etc., which she did not. Option 2 is unreasonable because not all the numbers are near 20 and should be rounded to their nearest whole numbers instead to find a more accurate estimate. Option 3 is unreasonable for the same reason as option 2, the numbers should be rounded to their nearest whole numbers instead to find a more accurate estimate. Option 4 is reasonable because the numbers are rounded to the nearest whole numbers which makes the estimate more accurate.
Volume of a cylinder = πr²h
1256 = (3.14) x (r)² x (13)
1256 = 40.82r²
r² = 1256 ÷ 40.82
r² = 30.769
r = √30.69
r = 5.547
Diameter = Radius x 2
Diameter = 5.547 x 2
Diameter = 11.09 units (nearest hundredth)
26500 + 725 = 27225
27225 x 0.06 = 1633.5
27225 + 1633.50 = 28858.50 + 50 = 28908.50 total cost
Its 15% because you have to divide 270 by 1800