Answer:
see explanation
Step-by-step explanation:
The sum to n terms of an arithmetic sequence is
=
[ 2a₁ + (n - 1)d ]
where a₁ is the initial value and d the common difference
Given
=
[ 10 + (n - 1)3 ]
Then by comparison
2a₁ = 10 ( divide both sides by 2 )
a₁ = 4 ← initial value
and d = 3 ← common difference
Thus
=
[ 10 + (7 × 3) ]
= 4(10 + 21)
= 4 × 31
= 124
There are 25 $10 bills and 11 $20 bills.
Step-by-step explanation:
Given,
Worth of proceeds from garage = $470
Let,
x be the number of $10 bills
y be the number of $20 bills.
According to given situation;
10x+20y=470 Eqn 1
x = y+14 Eqn 2
Putting value of x from Eqn 2 in Eqn 1
Dividing both sides by 30
Putting y=11 in Eqn 2
There are 25 $10 bills and 11 $20 bills.
Keywords: linear equation, substitution method
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