42. LO.4 Durell and Earline are married; file a joint return; and claim dependency exemptions for their two children, ages 5 years and 6 months. They also claim Earline’s son from a previous marriage, age 18, as a dependent. Durell and Earline’s combined AGI is

$68,000.

a. Compute Durell and Earline’s child tax credit.

b. Assume the same facts, except that Durell and Earline’s combined AGI is $122,000.

Compute their child tax credit.