u can solve it by substituting both the equation

so it becomes

3n < 2p < 4n

substituting 4 + n to p , we get

3n < 8 + 2n < 4n

finally
n < 8 < 2n

so n should be 5, 6, 7.
only 5 and 7 are prime and substituting in p = 4 + n, we get p as prime only for 7.

so answer will be 4 + 7 = 11

3/2<p/n<2
subtract 1 from this inequality,
1/2< (p-n)/n<1
= 1/2< 4/n < 1
multiplyby n
= n/2 < 4 < n
Now,n >4 and n/2<4.
put n=5
but if n=5 then p=9 which is npt prime.
put n=7,
p=11
11 is prime and also 11/7 =1.57 which lies between 1.5 and 2.
hence p=11

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