maths exercise

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f.1 maths
1.it takes a horse 1 min and 8.5 second to finish 1200 metres race. Change the unit of that time to min. and correct the answer to 4 sig. fig.

2.David finish a marathon 1 hour 24 min. and 17 seconds.
(a) Round off the unit of this time to hours, corr. to 4 sig. fig.

(b) Round off the unit of this time to min.corr to 4 sig fig

3. Juan measures that a box of pin (with 100 pieces inside) weights 168 g , and the relative error is 1/84.
find the possible range weight of each piece of pin


1.it takes a horse 1 min and 8.5 second to finish 1200 metres race. Change the unit of that time to min. and correct the answer to 4 sig. fig.

the time =60+8.5=68.5s=68.5/60 min=1.142 min

2.David finish a marathon 1 hour 24 min. and 17 seconds.
(a) Round off the unit of this time to hours, corr. to 4 sig. fig.

the time =1+24/60+17/(60*60)=1.405 hr

(b) Round off the unit of this time to min.corr to 4 sig fig

the time =1*60+24+17/60=84.28 min

or 1.405*60=84.28 min

3. Juan measures that a box of pin (with 100 pieces inside) weights 168 g , and the relative error is 1/84.
find the possible range weight of each piece of pin

the absolute error =[168*(1/84)]/100=0.02g

the maximum weight=1.68+0.02=1.70g

the minimum weight=1.68-0.02=1.66g

the range lies between 1.66 g and 1.70g

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F.1 Maths question
Shirley deposits $ 6000 in a bank at an interest rate of R% p.a. If the interest rate changes to5.5% p.a..She will get $180 more as the simple interest two years later .Find the value of R.



6000 * (5.5% - R%) * 2 = 180

12000 * (5.5-R)/100 = 180

5.5-R = 1.5

R = 5.5-1.5

R = 4

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