.
1. Two equations setup and solution
S + D = 175 (1)
S - D = 51 (2)
--------------------------- Add the equations to eliminate D:
2S = 175 + 51 = 226 ====> S =
= 113 (the number of sodas)
Then the number of dogs, from eq(1), D = 175 - S = 175 - 113 = 62.
Answer. 113 sodas and 62 dogs.
2. One equation setup and solution
sodas + dogs = 175
S + (S-51) = 175
2S - 51 = 175 ====> 2S = 175 + 51 = 226 ====> S =
= 113,
And you get the same answer.