Question

Ying Zyiyu covers the first 300 miles of a trip traveling at 60 mph. and the last hundred miles traveling at 40 mph. What was his average speed for the entire trip?

Answer 1

$We \:know \: that ,$

$\boxed { \pink { Time (t) = \frac{distance}{speed} }}$

$Here, i) Speed \: of \: first\: 300 \: miles \\(S_{1}) = 60\:mph$

$Distance (d_{1}) = 300 \:miles$

$\implies Time (t_{1}) = \frac{d_{1}}{s_{1}} \\= \frac{300}{60} \\= 5 \: hours \: --(1)$

$ii) Speed \: of \:last\: 100 \:miles \\(S_{2}) = 40\:mph$

$Distance (d_{2}) = 100 \:miles$

$\implies Time (t_{2}) = \frac{d_{2}}{s_{2}} \\= \frac{100}{40} \\= 2.5 \: hours \: --(2)$

$ii) Sum \: of \: distances = 300\: miles + 100\: miles \\= 400 \: miles \: --(3)$

$iv) Sum \: of \:the \: times = 5 + 2.5 \\= 7.5 \:hours \: -- (4)$

Therefore.,

$\red{ Average \: speed \: for \:entire \:trip } \\= \frac{(3)}{(4)} \\= \frac{400}{7.5} \\\green {= 53.33 \: mph}$

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Answer 2

Answer:

53.33

Step-by-step explanation:

ok, yall voted only 2/5 for the other explanation but it is correct. I tried it and it worked so...