CGPET 2017 Solved Paper

Crystal systems with a≠b≠c are
(i) Orthorhombic
(ii) Monoclinic
(iii) Triclinic
and crystal systems with a=b=c are
(i) Cubic
(ii) Rhombohedral (or Trigonal)
Hence,
Number of crystals with a≠b≠c⇒3 and
Number of crystals with a=b=c⇒2