A hint to get started
Infer mean and standard deviation from two tail areas
Blue Neon Guppy masses at Green Park Tropical Fish Farm are normal with mean μ g and standard deviation σ g.5% exceed 85 g and 10% are below 25 g. Find μ and σ, then find the range symmetric about the mean containing 75% of the masses.
CJC · Lecture · Example 6
Sketch the known tail and standardise its cutoff.
Use the N(0,1) quantile to build an equation for the unknown parameters.
Keep full precision until interpreting the final result.