Carcass wrote:
James' age is between that of Gwen and Lucille and is closer to Gwen's age than to Lucille's. Gwen is between 30 and 40 years old, inclusive. Lucille is less than 70 years old, and her age In years has exactly three prime factors. Which of the following could be James' age, in years?
Indicate all such ages.
❑ 15
❑ 18
❑ 22
❑ 37
❑ 42
❑ 52
❑ 65
A very simple solution:
For questions like this, you should always use the
min, max technique.Let J = James, L = Lucille, G = Gwen
We need min and max for L and G.
min of G = 30
max of G = 40
min of L = 8 (L's age in years has only three prime factors -
note its not three distinct prime factors)
max of L = 69 (L's age in years is less than 70.
Now when L = 8L(8)---------------------------G(30)-----------------------------------------G(40)Since J's age is closer to G than L, therefore it will be to the right of the mid point between 8 and 30. i.e. \((8+30)/2\)
L(8)-------------MID(19)-------------G(30)-----------------------------------------G(40)For our first range for the age of J is between
20 and 40. Note in this range, J's age will be between L and G and closer to G than L.Now when L = 69
G(30)--------------------------------G(40)-------------------------------------------------------L(69)Again we need to consider that J's age is closer to G than L. So we need the mid point between 40 and 69. i.e. (40+69)/2 = 54
[b]G(30)--------------------------------G(40)------------------------------MID(54)-------------------------L(69)
Earlier range for J's age was 19 to 40 but now it is extended till 54.
So the actual range is 19 to 54.
Only options C,D,E,F fall between this range.