186 because you would divide 341 by 11 and you get 31 then multiply that by 6 and you get 186. Did this help?
Answer:
6.11km/hr
Step-by-step explanation:
Let the speed that Kelli swims be represented by Y
Speed of the river = 5km/hr
Distance = Speed × Time
Kelli swam upstream for some distance in one hour
Swimming upstream takes a negative sign, hence:
1 hour ×( Y - 5) = Distance
Distance = Y - 5
She then swam downstream the same river for the same distance in only 6 minutes
Downstream takes a positive sign
Converting 6 minutes to hour =
60 minutes = 1 hour
6 minutes =
Cross Multiply
6/60 = 1/10 hour
Hence, Distance =
1/10 × (Y + 5)
= Y/10 + 1/2
Equating both equations we have:
Y - 5 = Y/10 + 1/2
Collect like terms
Y - Y/10 = 5 + 1/2
9Y/10 = 5 1/2
9Y/ 10 = 11/2
Cross Multiply
9Y × 2 = 10 × 11
18Y = 110
Y = 110/18
Y = 6.1111111111 km/hr
Therefore, Kelli's can swim as fast as 6.11km/hr still in the water.
Answer:
27.5 minutes
Step-by-step explanation:
Using,
R/R' = 2ᵃ/ᵇ------------------ Equation 1
From the equation,
R = mass of Element X before radioactive decay, R' = mass of element X after radioactive decay, a = Time taken, b = half life.
Given: R = 870 grams, R' = 154 grams, b = 11 minutes.
Substitute these values into equation 1
870/154 = 2ᵃ/¹¹
(870/154)¹¹ = 2ᵃ
Solve for a
2ᵃ = (5.649)¹¹
2ᵃ = 187061.26
Taking the logarithm of both side,
Log2ᵃ = Log(187061.26)
⇒ a = log(187061.26)/log2
a = 8.272/0.301
a = 27.5 minutes
