joyonugha940
Answered

A car travels a distance of 100km for 1h38min45sec.a)Round off the time to the nearest 1/4 hour b)Use the rounded time to find the average speed for the journey​



Answer :

Answer: 57.14 km/hr

Step-by-step explanation:  if an hour is divided into quarters it will be in increments of 15 minutes, since  one hour is 60 minutes.  60 minutes divided by 5 is 15 minutes.  

So 1 hour and 38 minutes is rounded off to 1 hour and 45 minutes.

this is 1 hour + 3/4 hour = 1 3/4 hour.  This is same as 1.75 hour

3/4 is .75

speed divided by the time will give the average speed.

100km/1.75hours  = 57.14 km/per hour

semsee45

Answer:

(a)  1 hour 45 min

(b)  57.1 km/h (nearest tenth)

Step-by-step explanation:

Given information:

  • Distance = 100 km
  • Time = 1 h 38 min 45 sec

[tex]\large\boxed{\sf Speed=\dfrac{Distance}{Time}}[/tex]

Part (a)

[tex]\begin{aligned}\sf \dfrac{1}{4}\;hour &= \sf 1 \; hour \div 4 \\& = \sf 60 \;mins \div 4\\& = \sf 15 \; mins\end{aligned}[/tex]

Therefore, the nearest ¹/₄ hours either side of the given time is:

  • 1 hour 30 min
  • 1 hour 45 min

1 h 38 min 45 sec is 8 min 45 sec more than 1 hour 30 min.

1 h 38 min 45 sec is 6 min 15 sec less than 1 hour 45 min.

Therefore, the nearest ¹/₄ hour to the given time is:  

  • 1 hour 45 min.

Part (b)

1 hour 45 min = 1.75 min (in decimal form)

Substitute the given distance and the rounded time (in decimal form) into the formula and solve for speed:

[tex]\begin{aligned} \implies \sf Speed & =\sf \dfrac{Distance}{Time}\\\\& = \sf \dfrac{100}{1.75}\\\\& = \sf 57.1\;km/h\;(nearest\;tenth)\end{aligned}[/tex]

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