Let
x = pounds of peanuts
y = pounds of cashews
z = pounds of Brazil nuts.
The total pounds is 50, therefore
x + y + z = 50 (1)
The total cost is $6.60 per pound for 50 pounds of mixture.
The total is equal to the sum of the costs of the different nuts.
Because the cost for peanuts, cashews, and Brazil nuts are $3, $10, and $9 respectively, therefore
3x + 10y + 9z = 50*6.8
3x + 10y + 9z = 340 (2)
There are 10 fewer pounds of cashews than peanuts, therefore
x = y + 10 (3)
Substitute (3) into (1) and (2).
y + 10 + y + z = 50
2y + z = 40 (4)
3(y + 10) + 10y + 9z = 340
13y + 9z = 310 (5)
From (4),
z = 40 - 2y (6)
Substitute (6) into (5).
13y + 9(40 - 2y) = 310
-5y = -50
y = 10
z = 40 - 2y = 40 - 20 = 20
x = y + 10 = 20
Answer:
Peanuts: 20 pounds
Cashews: 10 pounds
Brazil nuts: 20 pounds
If the integers have the same absolute value ... they're the same number
but with different signs ... then their sum is zero.
Example: (plus) 927 added to (negative) 927 = zero
If the integers have different absolute values ... they're different numbers with different
signs ... then their sum has the same sign as the one with the bigger absolute value.
Examples:
==> (plus) 92 added to (negative) 91
92 and 91 are 1 number apart on the number line.
The positive number is bigger than the negative number.
So the sum is +1 .
==> (plus) 35 added to (negative) 37
35 and 37 are 2 numbers apart on the number line.
The negative number is bigger than the positive one.
So the sum is -2 .
1/3+1/9= 4/9, which is a rational number. 1/3 is equal to 0.333333, which is equivalent to 1/3, while 1/9 is equal to 0.1111111. By adding we get 0.44444444, which is equal to 4/9.