upper bounds: Sinead ran 68m to nearest meter, in 9.8sec to nearest 10th of sec

bumblebee123

Junior Member
Joined
Jan 3, 2018
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200
Hi,

I have been struggling with calculations involving lower and upper bounds. I understand how to find out the bounds but when given a calculation my answers are always incorrect for example:

Sinead ran 68m to the nearest meter. Her time for the run was 9.8 seconds to the nearest tenth of a second. Calculate the upper bound for her average speed in m/s.

To answer I take the upper bound for distance and time then use the speed= distance/time

upper bound for distance: 68.5
upper bonder for time 9.85

68.5/9.85 = 6.9543...

However, the answer is : 7.02564

Can someone tell me where I am going wrong? Some questions I am getting right, most questions I get wrong, yet I use the same method. Thank you all in advance.
 
Hi,

I have been struggling with calculations involving lower and upper bounds. I understand how to find out the bounds but when given a calculation my answers are always incorrect for example:

Sinead ran 68m to the nearest meter. Her time for the run was 9.8 seconds to the nearest tenth of a second. Calculate the upper bound for her average speed in m/s.

To answer I take the upper bound for distance and time then use the speed= distance/time

upper bound for distance: 68.5
upper bonder for time 9.85

68.5/9.85 = 6.9543...

However, the answer is : 7.02564

Can someone tell me where I am going wrong? Some questions I am getting right, most questions I get wrong, yet I use the same method. Thank you all in advance.
Since you would be dividing by time, you need to use the lower bound of time (to calculate the upper bound of speed).
 
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