Nick is buying a birthday present for a friend the gift is on sale for 40% off. he has a coupon for an additional 20% off the sale price. write an expression to represent the cost of the gift. then write your expression in another form to show what percent of the original price nick will pay for his gift.

Let x = original price for the gift.

The gift is on sale for 40% off.
The sale price is x - 0.4x = 0.6x.

With a coupon for an additional 20% off the sale price, the new price is
0.6x - 0.2(0.6x) = 0.6x - 0.12x = 0.48x

The cost of the gift is 048x, where x = the original price.
The overall percent of the original cost is 48%

The discounted cost of the gift is 0.48x.
Nick pays 48% of the original price for the gift.
x = the original price of the gift.

Answer : The time taken by the element to decay to 2 grams is, 75.2 minutes

Step-by-step explanation:

Half-life = 13 min

First we have to calculate the rate constant, we use the formula :

Now we have to calculate the time passed.

Expression for rate law for first order kinetics is given by:

where,

k = rate constant  =

t = time passed by the sample  = ?

a = initial amount of the reactant  = 110 g

a - x = amount left after decay process =  2 g

Now put all the given values in above equation, we get

Therefore, the time taken by the element to decay to 2 grams is, 75.2 minutes