Number of sweets with Sekhar = x say.
Number of sweets given to Renu = 1/4 × x = x/4
Number of sweets given to Raji = 5
Till he has 7 sweets left.
x – ( x/4 + 5) = 7
⇒ x – x/4 – 5 = 7
⇒ x – x/4 = 7 + 5 = 12
⇒ \(\frac{4x\,-\,x}{4}\) = 12
⇒ 3x/4 = 12
⇒ x = 12 × 4/3 = 16
∴ x = 4 × 4 = 16
∴ Number of sweets with Sekhar at the beginning = 16