MATHS F.1 Q.2

2.anne typed 1000words at a speed of 30 words/min,and then typed 750words at a speed of 40 words/min.find her average typing speed.
2
The total word she has typed
=1000+750
=1750 words
The time she used
=(1000/30+750/40) min
her average typing speed
=(1750 words)/(1000/30+750/40) min
=(1750 words)/(52.08333) min
=33.6 words/min
3
3.joe took 10 minutes to ride a bicycle from home to the shore.the average speed of the whole journey was 600m/min.if his speed in the last 1/3 of his journey was 500m/min.
(a)find the time he took in the last 1/3 of his journey
(B)find his speed in the remaining journey.
(a)
The total distance from home to the shore
=10*600
=6000 m
The distance of his last 1/3 of his journey
=6000/3
=2000 m
The time he took in the last 1/3 of his journey
=2000/500
=4 min
(b)
The distance of his remaining 2/3 of his journey
=4000 m
He took 10-4=6 minutes to finish
So his speed in the remaining journey
=4000/6
=666.67 m/min