Suppose a drop of dye, with a concentration of 1 unit, is dropped at latex: x=0x = 0 at latex: t=0t = 0. at latex: t=5t = 5, the variance latex: (\sigma^2)( σ 2 ) of the concentration curve is found to be 20. estimate the diffusion coefficient latex: (d)

its 4 because 2 times 2 is 4, if you double the number two you get four

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.

a3+b= 60 (the amount of money you have)

we already know the cost of a=15 so replace a with $15

($15 x 3)+b=60

multiply 15 and 3 to get $45 and replace it with $45

45+b=60

and then replace b with 15 to get the total:

45+15=60

that means you have $15 left after buying 3 dictionaries.

15 divided by the cost of a map ($5) equals 3.

so you can buy 3 maps.

sorry if it was confusing!

not sure but it may be b, as i said i'm not sure.