Answer:
15 boys and 25 girls
Step-by-step explanation:
The sum of boys (b) and girls (g) is given as 40:
g + b = 40
The number of girls is 2 times the number of boys minus 5:
2b - 5 = g
First formula can be rewritten as g = 40 - b
Then you can substitute this for g in the second, and you get:
2b-5 = 40-b
Which simplifies to:
2b + b = 40 + 5
3b = 45
b = 15
g = 40-15 = 25
15 boys, 25 girls.
3:5=x:50
Therefore 5 ×x = 50
x = 10
Therefore 3 × 10 = 30
therefore 30 blue pens
proof = 30 blue + 50 red= 3+ 5
therefore 80 = 8x
Answer:
-12.5 i think
Step-by-step explanation:
230
because 5x23 is 115 x 2 which is 230
Answer:
2,674.14 g
Step-by-step explanation:
Recall that the formula for radioactive decay is
N = N₀ e^(-λt)
where,
N is the amount left at time t
N₀ is the initial amount when t=0, (given as 42,784 g)
λ = coefficient of radioactive decay
= 0.693 ÷ Half Life
= 0.693 ÷ 18
= 0.0385
t = time elapsed (given as 72 years)
e = exponential constant ( approx 2.7183)
If we substitute these into our equation:
N = N₀ e^(-λt)
= (42,787) (2.7183)^[(-0.0385)(72)]
= (42,787) (2.7183)^(-2.7726)
= (42,787) (0.0625)
= 2,674.14 g
