Please help me solve this situation:
There are two flocks of birds, one below the other. The lower flock says "If one of us goes up there, you will double our number. But if one of you goes down here, we will be equal in number." How many birds are there in each flock?
Let number in lower flock be L, and upper, U
Then, based on the 1st statement, U + 1 = 2(L - 1)____U + 1 = 2L - 2____U = 2L - 3 ------ eq (i)
Also, L + 1 = U - 1____L - U = - 2 ------ eq (ii)
L - (2L - 3) = - 2 ------- Substituting 2L - 3 for U in eq (ii)
L - 2L + 3 = - 2
- L = - 5
L, or number in lower flock = , or
5 - U = - 2 ----- Substituting 5 for L in eq (ii)
- U = - 2 - 5
U, or number in upper flock = , or
You can do the check!!