Im not good at this, thought Ive done Geometry, But for the first one (180-70) which should be 110, and for the second one I would say 55.
Let x = the number.
"increased by" tells you we are adding.
"twice a number" tells you 2 times a number.
16 + 2x = - 24
Subtract 16 from both sides so that we have the variable on one sides and the constants on the other.
2x = - 24 - 16
2x = - 40
Divide by 2 to isolate the variable.
x = - 40/2 = - 20
Your solution is - 20.
To check your answer, plug in.
16 + 2(-20) = - 24
16 - 40 = - 24
- 24 = - 24
Let us convert the percentages to decimal format first.. so 5% is just 5/100 or 0.05 and 15% is just 15/100 or 0.15
so hmmm, so, let's say it needs "x" amount and "y" amount of each respectively, so, whatever "x" and "y" are, they must add up to 100, and whatever their concentration is, must add up to what the mixture yields
thus

solve for "x"
what's "y"? well, y = 100 - x
The answer is c because it’s not a or d and maybe not b so ye c