A rectangular concrete beam has a width of $250mm$ and an effective

depth of $450mm.$ The beam is simply supported over a span of $6m$ and

is used to carry a uniform dead load of $5K\frac{N}{m}$ and a uniform live load

of $6K\frac{N}{m}.$ Self$-$weight of the beam is neglected. Assume $f^{\text{'}}c=$

$21$MPa, and $fy=312$MPa. Use $20-mm$ bars, in one horizontal

layer.

i$.$ What is the required tension steel area in $m{m}^2?$

ii$.$ Determine the number of longitudinal bars.