The answer for this looks wrong

[sherry_d]

We have a question in IPS practice and we think the answer in the book is wrong but here we go

Duncan is twice as old as Sebastian will be next year. Isabella is 8. Sebastian is three years older than Isabella was last year

How many years old is Duncan?

[stevew61]

We have a question in IPS practice and we think the answer in the book is wrong but here we go

Duncan is twice as old as Sebastian will be next year. Isabella is 8. Sebastian is three years older than Isabella was last year

How many years old is Duncan?

Sometimes use a timeline, but hard to draw on here, this question suits,

d = 2 (s+1)

i = 8

s = i + 3 -1

so s = 8 + 3 -1 = 10

so d = 2 (10+1)

d=22

Maybe ignore the brackets and stick to phrases.

How did I score?


steve

[Twinkle]

Duncan is 22.

[twinkles]

I make it that Duncan is 22?

[hermanmunster]

I =8
S=10
d=11

What does the book say??

[sherry_d]

The answer is 14 in the book

We did work Duncan out to be 19 though

I have checked the question to make sure it is exact like it is in the book and it is....I dont think its 22 re read the question

[twinkles]

How did you come to your figure of 19 then?

[hermanmunster]

We have a question in IPS practice and we think the answer in the book is wrong but here we go

Duncan is twice as old as Sebastian will be next year. Isabella is 8. Sebastian is three years older than Isabella was last year

How many years old is Duncan?

Isabella was 7 last year
Sebastian is now 3 years older than Isabella was ie 10
Next year seb will be 11
so duncan is 11*2 now

[sherry_d]

Actually 22 is the right answer ....I got vexed a bit where it says Duncan is twice as old as Sebastian will be next year.

I took it Duncan will be 20next year less the one year which is obviously wrong.

But the book still got it wrong. The answers they have are 15, 12, 18, 14, 16 and 14 being the answer

[hermanmunster]

can't be 19 as he has to be twice sebastian's age