A motorist average 48km/hr for the first 30km of a journey and 64 km/hr for the next 120km what is the avera-
ge speed of the whole journey

120/30=4

So we have 5 equal segments of 30 km to work with.

4 segments at 64km/h and 1 segment at 48km/h.

Add them up 64+64+64+64+48=304

304 divided by total segments of 5 = 60.8km/h for the trip

Step-by-step explanation:

a

b

d

step-by-step explanation:

geometry: triangles

solvers

lessons

answers archive

call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

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