is the number <em>L</em> such that
Consider the first 7 multiples of 5:
5, 10, 15, 20, 25, 30, 35
Taken mod 7, these are equivalent to
5, 3, 1, 6, 4, 2, 0
This tells us that 3 is the inverse of 5 mod 7, so <em>L</em> = 3.
Similarly, compute the inverses modulo 7 of 2 and 3:
since 2*4 = 8, whose residue is 1 mod 7;
which we got for free by finding the inverse of 5 earlier. So
and so <em>R</em> = 2.
Then <em>L</em> - <em>R</em> = 1.
Step-by-step explanation:
1) if (0;0) if point A, (1;2) is point B; (-1;-2) is C, (2;1) is D, then
2) the vector AB is (1;2); vector AC is (-1;-2) and vector AD is (2;1), then
3) the length of AB, AC and AD are:
4) if the lengths above are equal, then it means that (0, 0) is equidistant from (1, 2), (-1, -2) and (2, 1).
With 37 mangoes you can bake 12 fruit tarts, because you need 3 mangoes for each tarts and you'll use mangoes. The remaining mango is not enough for another tart.
On the other hand, in order to bake 12 tarts, you'll need 24 apples, because you need 2 apples per tart.
So, with 12 apples and 37 mangoes you can bake 12 tart, with one mango as leftover.