Step-by-step explanation:
from E = mc^2 and de Broglie wavelength=h/mc
combine the eqns with respect to m(considering the body is moving with the speed of light(c))
then
E= hc/de Broglie wavelength
since, c= 3× 10^ 8
h= 6.626 × 10^ -34 and E is given, substitute the values.
sorry I don't have my calculator.