Can any one solve this problem please?

Question

a 4:1 ratio step-down transformer takes 1 A at 0.15 power factor on no load. Determine the primary current and power factor when the transformer is supplying a load of 25 A at 0.8 power factror lag. Ignore internal voltage drops.

Answer 1

Ino load = 1(0.15+j 0.9887)

I load referred to the primary is= 25/4(0.8+j 0.6)

I primary total = 5.15 +j4.9887 A

tan @= 4.9887/5.15=0.9687 so cos @=0.7183 ( power factor)

Primary current = sqrt(5.15^2+4.99^2)=7.17 A