Question
The average age of 16 girls is 35 years. If the age of
two more girls is added the average decreases by 3.5 years. What is the sum of the age of new girls?Solution
Total age of 16 girls = 16 × 35 = 560 years  If the age of two more girls is added the average decreases by 3.5 years,  ∴ Total age of 18 girls = 31.5 × 18 = 567 Now, the sum of the age of new girls = 567 – 560 = 7 years
The minimum value of 45 sin2 θ + 28 cos2 θ is

Evaluate the following:
sin 60° × cos 30° + sin 30° × cos 60°
If 4sin² θ = 3(1+ cos θ), 0° < θ < 90°, then what is the value of (2tan θ + 4sinθ - secθ)?
- If 2cos²A + 3sin²A = 13/5, then find the value of (sec²A - 1)
- If sin (a + b) = (√3/2) and cos (a – b) = (√3/2), then find sin a.

sin2 17˚ + sin2 19˚ + sin2 21˚ + sin2 23˚ + ……… + sin2 77˚ = ?
If tan² 45°- cos² 60° x sin 45° cos 45° cot 30°, then find the value of 'x'.
If SecA + TanA = 2√2 + 9, then find the value of Sin A + Cos A.