Answer:
A) 277 million years
Step-by-step explanation:
Here, decay of U-238 is first order reaction. (since most of the nuclear decays are first order).
so, the equation t =
× ln(
)
where, t = time from start of reaction
k = reaction constant
A(0) = initial concentration; A = present concentration.
⇒ 4.5 billion = 4500 million years =
× ln2.
Now, given 95.82% of parent U-238 isotope is left.
⇒ t =
× ln(
)
t =
× ln(
)
⇒ t ≅ 277 million years.
Answer:
z=70, y=102
Step-by-step explanation:
180-110 = 70
so, z=70
99+89+70 = 258
360-258 = 102
so, y=102
Answer:
13x + 112 = 320.
Step-by-step explanation:
The perimeter is the sum of the 3 sides:
1/2 x + 3/8 x + 11 + 3/4 x + 3 = 40
1/2 x + 3/8 x + 3/4 x + 3 + 11 = 40
1/2 x + 3/8 x + 3/4 x + 14 = 40
Multiply through by 8 to remove the fractions:
4x + 3x + 6x + 14 = 40
13x + 112 = 320.
Answer:
Given - Two angles measures 2x and 3x
To find - size of 3x
Solution -
2x + 3x = 360° ( Make reflex angle )
5x = 360°
x = 360/5
x = 72°
3x = 3 * 72 = 216°