There are several information's already given in the question. Based on those information's the answer can be easily deduced.
Distance traveled by the bicycle rider = 50 km
Time taken to travel the distance = 2.5 hours
So
In 2.5 hours the bicycle rider travels = 50 km
Then
In 1 hour the bicycle rider travels = 50/2.5
= 20 km
Then the average speed of the cyclist is 20 km per hour.
The first one is A and the second one would be C
The product of speed and time is distance. To calculate the total distance you multiple the speed in kilometers per second by the time at that speed in seconds, do this for all 3 different speeds then add them up, the 17.4 minutes eating does not affect the answer at all. to convert from minutes to seconds multiply time in minutes by 60, to convert from km/h to km/s divide km/h by 3600.
(23.5x60)x(74.5/3600) = 29.2km (rounded to 1 decimal place)
+
(15.9x60)x(111/3600) = 29.4km (rounded to 1 decimal place)
+
(49.2x60)x(38.7/3600) = 31.7km
=90.3km
The brackets are not necessary but i think it makes it more clear what is happening in your working.
4. hyperdermis is not a layer of skin
Density<span> is the </span>mass<span> of an object </span>divided<span> by its </span>volume<span>. So the answer would be Yes. Hope it helps! (:</span>