Benito is selling T-shirts for $8 each for his school fund-raiser. So far, he has sold 16 T-shirts. How many more does he need t
2 answers:
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Answer:
see explanation
Step-by-step explanation:
The nth term of an AP is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given a₅ is double a₇ , then
a₁ + 4d = 2(a₁ + 6d) , that is
a₁ + 4d = 2a₁ + 12d ( subtract a₁ from both sides )
4d = a₁ + 12d ( subtract 12d from both sides )
- 8d = a₁
The sum of n terms of an AP is
=
[ 2a₁ + (n - 1)d ] , substitute values
=
( 2(- 8d) + 16d)
= 8.5(- 16d + 16d)
= 8.5 × 0
= 0
Answer:
- Initial amount of the material is 67 kg
- Hal-life is 83 hours
<u>The required equation is:</u>
- m(x) = 67 *
, where m- remaining amount of the radioactive material, x - number of hours
<u>After 5 hours the material remains:</u>
- m(5) = 67 *
= 64.260 (rounded)