If $20$ samples of a production process are taken and there are $240$ total defects, the upper and lower control limits for a $3.$sigma c$-$chart are UCL $-18\mathrm{.}728,$ LCL $-5\mathrm{.}272$ UCL $=15,464,$ LCL $=8,536$ UCL $-22\mathrm{.}392,$ LCL $-1\mathrm{.}608$ UCL $-16\mathrm{.}472,$ LCL$-7\mathrm{.}528$