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Ksivusya [100]
3 years ago
14

It takes an older employee 13 hours to shovel the snow from a sidewalk, but a younger employee can shovel the same sidewalk in 1

0 hours. how long will it take them to clear the walk if they work together?
Mathematics
1 answer:
Ket [755]3 years ago
7 0
Work in rates per hour. These rates can then be added to form an equation

1/13 + 1/10  = 1/x   where  x is the time for both working together

multiply thru by 130x:-

10 x+ 13 x =  130

x = 130/23 =  5.65 hours  or about  6 hours 39 minutes
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Strontium-90 has a half-life of 28.8 years. If you start with a 300-gram sample of strontium-90,
Kazeer [188]

Answer:  2.66 × 10⁻¹³

<u>Step-by-step explanation:</u>

First, use the decay formula   A=A_oe^{kt}   where

  • A is the final amount (amount left)
  • A₀ is the initial amount (amount you started with)
  • k is the rate of decay (you need to solve for this)
  • t is the time

Given:

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  • A₀ = 300
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150=300e^{28.8k}\\\\0.5=e^{28.8k}\\\\ln(0.5)=ln(e^{28.8k})\\\\ln(0.5)=28.8k\\\\\\\dfrac{ln(0.5)}{28.8}=k\\\\\\\large\boxed{-0.0240676=k}\\

Next, input the k-value and the new t-value to solve for A.

  • A = unknown
  • A₀ = 300
  • k = -0.0240676
  • t = 1440

A=300e^{1440(-.0240676)}\\\\\large\boxed{A=2.66\times 10^{-13}}\\

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3 years ago
How is multiplication using partial products different from multiplication using regrouping?
klio [65]
Partial products is breaking down every number in multiplication and adding them. Regrouping is grouping number them adding them.They are alike because they both involve breaking down the numbers and adding them.  They are different because one is taking all the numbers broken down, while the other is just a couple of the number.
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Aleonysh [2.5K]
Hi! 
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egoroff_w [7]

Answer:

cos 60° = 1/2 because the angles are complements.

Step-by-step explanation:

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