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From the condition, the cost of one orange is 50 cents and the cost of one apple is 50 - 10 = 40 cents.
Let x be the number of apples.
40x + 50*(9-x) = 410 cents ====> 40x + 450 - 50x = 410 ====> -10x = 410-450 = -40 ====> x = 4.
Answer. 4 apples and 9-4 = 5 oranges.
There are 3 (three) ways to solve this problem.
1. Writing the system of 2 equations in two unknowns.
2. Using one equation and one unknown (it is what I did in my post)
3. To solve the problem MENTALLY, without using equations.
It is what the tutor @greenestamps did in his post.
See the lessons
- Problem on two-wheel and three-wheel bicycles,
- Problem on animals at a farm and
- Problem on pills in containers
in this site, where similar problems were solved using all three methods.