Answer:
9 cans of soup and the 4 frozen dinners were purchased
Step-by-step explanation:
Let x represent the number of cans of soup purchased.
Let y represent the number of frozen dinners purchased.
Lincoln purchased a total of 13 cans of soup and frozen dinners. This means that
x + y = 13
Each can of soup has 250 mg of sodium and each frozen dinner has 550 mg of sodium. The 13 cans of soup and frozen dinners which he purchased collectively contain 4450 mg of sodium. This means that
250x + 550y = 4450 - - - - - - - - -1
Substituting x = 13 - y into equation 1, it becomes
250(13 - y) + 550y = 4450
3250 - 250y + 550y = 4450
- 250y + 550y = 4450 - 3250
300y = 1200
y = 1200/300
y = 4
Substituting y = 4 into x = 13 - y, it becomes
x = 13 - 4 = 9
Decimal points must be aligned with performing addition or subtraction.
The arithmetic operation that does <em>not</em> require decimal points be aligned is multiplication.
_____
For multiplication, you only need to know the number of digits to the right of the decimal point(s).
For long division, it is usually convenient to convert the divisor to an integer and adjust the decimal point of the dividend accordingly. Alternatively, it is necessary to know the number of digits in each number that are to the left of the decimal point.
Answer:
2310
Step-by-step explanation:
