Answer:
North America has 23 countries
Europe has 46 countries
Africa ha 53 countries
Step-by-step explanation:
Firstly to answer the question, we define variables. Let the number of countries in Africa be A, the number of countries in europe be E while the number of countries in North America be N.
Firstly, we are told there are a total number of 122 countries. Mathematically this means the addition of all the countries will give 122
Hence;
N + A + E = 122. •••••••(i)
Secondly we are made to know that Europe has twice as many countries as North America;
Mathematically l, this means
E = 2N. •••••••••(ii)
Thirdly we know that Africa has 7 more countries than Europe;
This mathematically means that
A = E + 7. •••••••••(iii)
Since E = 2N, A = 2N + 7 ••••••••(iv)
Now what to do to find the answer is to substitute equation ii and iv at the same time into equation i
This will give the following;
N + 2N + 2N + 7 = 122
5N = 122 - 7
5N = 115
N = 115/5
N = 23
We recall
E = 2N = 2(23) = 46
Also
A = 2N + 7 = 46 + 7 = 53
