Answer:
150 mL
Step-by-step explanation:
Let x represent the quantity of 75% solution needed. The total amount of alcohol in the 60% mixture will be ...
75%·x + 10%·45 = 60%·(x+45) . . . . . there will be x+45 mL of solution in the end
0.15x = 22.5 . . . . . . . . . . . . . . . . . . . . simplify, subtract .60x+4.5
22.5/0.15 = x = 150 . . . . . . . . . . . . . . mL of 75% solution needed
You will need 150 mL of the 75% solution.
Answer:
b 2/7
Step-by-step explanation:
Because there is a 6/21 chance and 2/7=6/21
Answer:
3.9 mi/h
Step-by-step explanation:
If the boy is rowing perpendicular to the current, the two vectors form a right triangle.
AB represents the downstream current, BC is the speed across the river, and AC is the ground speed of the boat
AC^2 = 2.4^2 + 3.1^2 =5.76 + 9.61 = 15.37
AC = sqrt(15.37) = 3.9 mi/h
The boat's speed over the ground is 3.9 mi/h.
So, if the first person takes half of the pizza, half of the pizza is left.
If the second person takes half of the amount the first person took, that would be a quarter of the pizza left.
TL;DR - There is 1/4 of the pizza left
