In an npn power transistor the collector current is 20mA. If 98 percent of the electrons injected into base region reach collector then the base current in mA is nearly ?
Here, in this problem is it okay to take \$\beta=I_c/I_b=98/2=49\$ ?
It sounds like they mean 98% of the emitter current, not the base current. That means you're given \$\alpha = 0.98\$. You can use that to calculate \$\beta\$ and find the base current.
You don't need to know \$\beta\$ to answer the question. Just Kirchoff's Current Law.