Right now christina is twice as old as mark. in five years, she will be 50% older than him. how many years old is christina now?

Christina is 10 years old now

Step-by-step explanation:

- Right now Christina is twice as old as mark

- Assume that mark now is x years old

∵ Mark is x years old

∵ Christina is twice as old as mark

∴ Christina is 2 x years old

- In five years, she will be 50% older than him

∵ Mark is x years old now

∴ In five years mark will be x + 5 years old

∵ Christina is 2 x years old now

∴ In five years Christina will be 2 x + 5 → (1)

∵ In five years Christina will be 50% older than him

- Assume that he will be 100% year and she is older by 50%, then she

  will be 150% ⇒ (100% + 50%)

∵ 150% =

∴ In five years Christina will be 1.5(x + 5) → (2)

- Equate (1) and (2)

∴ 2 x + 5 = 1.5(x + 5)

- Simplify the right hand side

∴ 2 x + 5 = 1.5 x + 7.5

- Subtract 1.5 x from both sides

∴ 0.5 x + 5 = 7.5

- Subtract 5 from both sides

∴ 0.5 x = 2.5

- Divide both sides by 0.5

∴ x = 5

∵ x represents the age of Mark now

∴ Mark now is 5 years old

∵ Christina is twice as old as Mark now

∴ Christina is 10 years old

* Christina is 10 years old now

c

step-by-step explanation:

answer: the angel abc is 30°,and the abc is a triangle where the angel bac is 90°

so ac is the half of 24=12ft,and from the pythagorean theorem we find ba

ba=√bc^2-ac^2=√576-144=√432=12√3ft

so bac is 12+12√3=12(1+√3)ft