If the ratio of U-238 to Pb-206 atoms is 1:1, how old is
the zircon crystal?

answer; i believe the correct answer is (solid gold);

i need mutiple choices

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer