The half-life of a certain substance is 18 years. how long will it take for a sample of this substance to decay to 63% of its original amount?

It will take 12 years to decay 63% of the substance.

Step-by-step explanation:

Given information:

The half life of substance = 18 years

Now , we know that

where,

initial mass

decay constant

time

now put the values in above equation:

As:

Now for 63% decay , we can write as:

Hence, it will take 12 years to decay 63% of the substance.

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d) 30 units^2

area of rectangle = l × b

we know,

length = 10 unit

breadth = 3 unit

applying the formula,

= l × b

= 10 × 3

= 30 unit^2

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a function could be identified in 3 ways either on a chart,graph, or ordered pairs. first a function is that each point has its own. the rule is that there can be many x's to one y but there can not be 2 x's at different y's. so on a graph when you put a straight line through the y's there should be one dot only to be a function.

step-by-step explanation: