Answer:
she bought 20 chocolates
Step-by-step explanation:
let c be the number of chocolates and s the number of sweets she bought.
The number of sweets s , is 3 times the number of chocolates c, that is
s = 3c → (1)
She then gives 3 of each away , that is she now has
s - 10 sweets and c - 10 chocolates
Now the number of sweets is 5 times the number of chocolates , that is
s - 10 = 5(c - 10) = 5c - 50 → (2)
substitute s = 3c into (2)
3c - 10 = 5c - 50 ( subtract 3c from both sides )
- 10 = 2c - 50 ( add 50 to both sides )
40 = 2c ( divide both sides by 2 )
20 = c
from (1) : s = 3c = 3 × 20 = 60
She bought 20 chocolates and 60 sweets