Shrinkage allowance on pattern is provided to compensate for shrinkage when

Molten aluminium was poured in a sand mold and the thickness of solid skin formed after $$20$$ seconds and $$50$$ seconds were fond to be $$3mm$$ and $$4.5mm$$ respectively. What would be the thickness of the solid skin at the end of $$100$$ seconds after pouring?

In welding brass with oxy-acetylene flame, the type of flame used is

In welding a mild steel sheet using an oxy-acetylene flame, the total amount of acetylene consumed was $$8.0$$ liters the oxygen consumption from the cylinder is