the ratio of land to water on Earth is 1 is to 2 in the ratio of the land to water in Northern hemisphere is 2 is to 3 then find the ratio of land to water in Southern hemisphere
Answers
Answer:
(a) For the whole earth land =
1+2
1
=
3
1
,
water=
1+3
2
=
3
2
∴Forthenorhternhemisphereland=
5
2
×
2
1
=
5
1
andwater=
5
3
×
2
1
=
10
3
asnorthernhemisphere=
2
1
ofwholeearth.
∴southernhemisphere,land=
3
1
−
5
1
=
15
5−3
=
15
2
Water=
3
2
−
10
3
=
30
20−9
=
30
11
∴Requiredratioofland:waterinsouthernhemisphere=
15
2
:
30
11
=4:11.
Answer:
This is one of those problems where, at least for me, setting up the equations is a confusing and time consuming endeavor. Sometimes, a strategy that works quite well in this scenario is substituting in random numbers. Let us assume that the surface area of the earth is 30 square meters (This isn't actually random, because I can foresee I will have to divide by two, five, and three in the near future and I don't like fractions. If you don't believe me, just watch.)
Since the ratio of land to water on Earth is 1:2, there are 10 sq. meters of land and 20 sq. meters of water on Earth (see, there's the division by three).
Since the Northern Hemisphere accounts for half of the earth's surface area (here comes division by two!) there are 15 square meters total in the Northern Hemisphere; since the land-to-water ratio for the Northern Hemisphere only is 2:3, there are 6 sq. meters of land and 9 sq. meters of water there (there's the division by five).
Given that there is 10 sq. meters land total and 6sq. meters in the North, there must be 4 sq. meters of land in the Southern Hemisphere. By the same argument, there are 11 sq. meters of water in the South. Therefore, the ratio of land to water in the Southern Hemisphere is 4:11.
Explanation: