Answer: the number of physics textbook sold in the week is 138
the number of maths textbook sold in the week is 69
Step-by-step explanation:
Let x represent the number of physics textbook sold in the week.
Let y represent the number of maths textbook sold in the week.
A textbook Store sold a combined total of 207 physics and math textbooks this week. This means that
x + y = 207 - - - - - - - - - - - - 1
The number of physics textbooks sold was two times the number of math textbook sold. This means that
x = 2y
Substituting x =2y into equation 1, it becomes
2y + y = 207
3y = 207
y = 207/3 = 69
x = 2 × 69
x = 138
