Joseph and Patrick purchased school supplies in the school bookstore Joseph purchases for notebooks and three pans for $11 Patrick purchases three notebooks and five pens for $11 what is the price of a notebook what is the price of a pen

We can make a system of equations:

Joseph: 4n+3p=11

Patrick: 3n+5p=11

Luckily enough, they are both equal to 11, so this is easy to solve. Just put the two together like this and solve for n:

4n+3p=3n+5p

n+3p=5p

n=2p

Plug 2p into either equation for n:

4(2p)+3p=11

8p+3p=11

11p=11

p=1

So a pen is $1, and that must mean a notebook must be $2 because it costs twice as much as a pen.

Hope this helped! Feel free to message me with any more questions.

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)