Wendy kept track of the number of text messages she sent each day for 3 weeks complete the frequency table

multiply each number by ten to get a simplified answer of 7/1.

let x be volume of 1% and let y represent volume of 7% solution.

then the amount of minoxidil is

0.01x + 0.07y = 0.05(x+y)

but we have that x = 90 ml so

0.01(90) + 0.07y = 0.05(90+y)

0.9 + 0.07y = 4.5 + 0.05y

0.02y = 4.5-0.9

y = 3.6/ 0.02

y = 180 ml

she should add 180 ml of 7%